Multicopter-assisted system and method for launching and retrieving a fixed-wing aircraft

ABSTRACT

The present disclosure provides various embodiments of a multicopter-assisted launch and retrieval system generally including: (1) a multi-rotor modular multicopter attachable to (and detachable from) a fixed-wing aircraft to facilitate launch of the fixed-wing aircraft into wing-borne flight; (2) a storage and launch system usable to store the modular multicopter and to facilitate launch of the fixed-wing aircraft into wing-borne flight; and (3) an anchor system usable (along with the multicopter and a flexible capture member) to retrieve the fixed-wing aircraft from wing-borne flight.

PRIORITY CLAIM

This patent application is a continuation of and claims priority to andthe benefit of U.S. patent application Ser. No. 15/431,253, filed onFeb. 13, 2017, which is a continuation of and claims priority to and thebenefit of U.S. patent application Ser. No. 15/375,909, filed on Dec.12, 2016, now U.S. Pat. No. 10,569,868, which issued on Feb. 25, 2020,and:

-   -   (1) claims priority to and the benefit of U.S. Provisional        Patent Application No. 62/269,629, filed on Dec. 18, 2015; and    -   (2) is a continuation-in-part of and claims priority to and the        benefit of U.S. patent application Ser. No. 15/144,119, filed on        May 2, 2016, now U.S. Pat. No. 9,656,765, which issued on May        23, 2017, and which is a continuation of and claims priority to        and the benefit of U.S. patent application Ser. No. 14/597,933,        filed on Jan. 15, 2015, now U.S. Pat. No. 9,359,075, which        issued on Jun. 7, 2016, which is a continuation-in-part of and        claims priority to and the benefit of U.S. patent application        Ser. No. 14/230,454, filed on Mar. 31, 2014, now U.S. Pat. No.        10,144,511, which issued on Dec. 4, 2018, which claims priority        to and the benefit of:    -   (a) U.S. Provisional Patent Application No. 61/808,392, filed on        Apr. 4, 2013; and    -   (b) U.S. Provisional Patent Application No. 61/807,508, filed on        Apr. 2, 2013.

The entire contents of each of the above-identified patent applicationsare incorporated herein by reference.

BACKGROUND

It is well-known in the aeronautical sciences that an aircraft capableof hover and/or of slow flight is typically not well-suited tolong-distance efficient cruising flight. One drawback of aircraftcapable of long-distance efficient cruising flight is that such aircrafttypically require long runways to be utilized for take-off and landing.This becomes problematic when there is not sufficient space for therequisite runway, meaning that such aircraft may not be used. There is aneed for new systems and methods by which aircraft that otherwiserequire a long runway may be launched and retrieved from small spacesthat solve these problems.

SUMMARY

The rotorcraft-assisted launch and retrieval system of variousembodiments of the present disclosure generally includes: (1) aneight-rotor modular multicopter attachable to (and detachable from) afixed-wing aircraft to facilitate launch of the fixed-wing aircraft intowing-borne flight; (2) a storage and launch system usable to store themodular multicopter and to facilitate launch of the fixed-wing aircraftinto wing-borne flight; and (3) an anchor system usable (along with themulticopter and a flexible capture member) to retrieve the fixed-wingaircraft from wing-borne flight.

Generally, to launch the fixed-wing aircraft into wing-borne flight, anoperator (or operators): (1) removes the disassembled multicopter from acontainer of the storage and launch system; (2) assembles themulticopter; (3) mounts the fixed-wing aircraft to a launch-assistassembly of the storage and launch system; (4) attaches the fixed-wingaircraft to the multicopter; (5) remotely controls the multicopter tolift the fixed-wing aircraft to a desired altitude and to accelerate thefixed-wing aircraft to a desired speed; and (6) remotely causes thefixed-wing aircraft to detach from the multicopter, thereby releasingthe fixed-wing aircraft into wing-borne flight.

Generally, to retrieve the fixed-wing aircraft from wing-borne flight,the operator (or operators): (1) attaches one end of a flexible capturemember to the multicopter and the other end to the anchor system; (2)remotely controls the multicopter to fly above the anchor system untilthe flexible capture member is tensioned to a designated level; and (3)controls the fixed-wing aircraft to capture the flexible capture member.

Additional features and advantages of the present disclosure aredescribed in, and will be apparent from, the following DetailedDescription and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1A is a top perspective view of one example embodiment of themulticopter of the present disclosure attached to a fixed-wing aircraft.

FIG. 1B is a top plan view of the multicopter and fixed-wing aircraft ofFIG. 1A.

FIG. 1C is a top perspective view of the multicopter of FIG. 1A.

FIG. 1D is a bottom perspective view of the multicopter of FIG. 1A.

FIG. 1E is a partially exploded top perspective view of the multicopterof FIG. 1A.

FIG. 1F is a partially exploded bottom perspective view of themulticopter of FIG. 1A.

FIG. 1G is a block diagram showing certain electrically controlledcomponents of the multicopter of FIG. 1A.

FIG. 2A is a top perspective view of the hub module of the multicopterof FIG. 1A.

FIG. 2B is a bottom perspective view of the hub module of FIG. 2A.

FIG. 2C is a partially exploded top perspective view of the hub moduleof FIG. 2A showing the hub base separated from the saddle.

FIG. 3A is a top perspective view of the hub base of the hub module ofFIG. 2A.

FIG. 3B is a bottom perspective view of the hub base of FIG. 3A.

FIG. 3C is a partially exploded top perspective view of the hub base ofFIG. 3A.

FIG. 3D is an exploded top perspective view of the supports andassociated mounting hardware of the hub base of FIG. 3A.

FIG. 3E is an exploded top perspective view of the isolator plate andassociated mounting hardware of the hub base of FIG. 3A.

FIG. 3F is a partial cross-sectional view of one of the isolator platemounts of the hub base of FIG. 3A taken substantially along line 3F-3Fof FIG. 3C.

FIG. 3G is a partially exploded top perspective view of one of thefemale blind mate assemblies of the hub base of FIG. 3A.

FIG. 3H is a partial cross-sectional view of one of the flexural mountsof the female blind mate assembly of FIG. 3G taken substantially alongline 3H-3H of FIG. 3C.

FIG. 4A is a top perspective view of the saddle of the hub module ofFIG. 2A.

FIG. 4B is a bottom perspective view of the saddle of FIG. 4A.

FIG. 4C is a partially exploded top perspective view of the saddle ofFIG. 4A.

FIGS. 4D and 4E are side elevational views of the saddle of FIG. 4Ashowing different positions of the saddle.

FIG. 4F is a top perspective view of the cam of the saddle of FIG. 4A.

FIG. 4G is an exploded top perspective view of the aircraftattaching/detaching assembly and the cam of the saddle of FIG. 4A.

FIG. 4H is a partial cross-sectional view of the saddle of FIG. 4A takensubstantially along line 4H-4H of FIG. 4C.

FIG. 4I is a partial cross-sectional view of the saddle of FIG. 4Ashowing the cam in a detached rotational position taken substantiallyalong line 4H-4H of FIG. 4C.

FIG. 5A is a top perspective view of one of the rotor arm modules of themulticopter of FIG. 1A.

FIG. 5B is a bottom perspective view of the rotor arm module of FIG. 5A.

FIG. 5C is a top perspective view of the locking assembly of the rotorarm module of FIG. 5A.

FIGS. 5D, 5E, and 5F are side elevational views of the rotor arm moduleof FIG. 5A detaching from the hub module of FIG. 2A via the lockingassembly of FIG. 5C.

FIG. 5G is an exploded top perspective view of one of the rotor armassemblies and part of the rotor assembly of the rotor arm module ofFIG. 5A.

FIG. 5H is a cross-sectional view of the rotor motor assemblies of therotor arm module of FIG. 5A taken substantially along line 5H-5H of FIG.5A.

FIG. 5I is an exploded top perspective view of one of the rotor motorcollars and one of the rotor motor fans of the rotor arm module of FIG.5A.

FIG. 5J is a cross-sectional view of the rotor assembly of the rotor armmodule of FIG. 5A taken substantially along line 5J-5J of FIG. 5A.

FIG. 6A is a top perspective view of one of the front landing gearextension modules of the multicopter of FIG. 1A.

FIG. 6B is a top perspective view of one of the rear landing gearextension modules of the multicopter of FIG. 1A.

FIG. 7A is a top perspective view of one of the front landing gearmodules of the multicopter of FIG. 1A.

FIG. 7B is a top perspective view of one of the rear landing gearmodules of the multicopter of FIG. 1A.

FIG. 8A is a partially exploded top perspective view of the multicopterof FIG. 1A stored in one example embodiment of the storage and launchsystem of the present disclosure.

FIG. 8B is an exploded top perspective view of the storage and launchsystem of FIG. 8A, the 13 modules of the multicopter of FIG. 1A, andelements used to store the multicopter.

FIG. 8C is a top perspective view of the launch-assist assembly of thestorage and launch system of FIG. 8A in the launch position.

FIG. 8D is a top perspective view of the storage and launch system ofFIG. 8A with the fixed-wing aircraft mounted thereto.

FIG. 8E is an exploded top perspective view of the fuselage-retainingassembly of the launch-assist assembly of FIG. 8C.

FIG. 8F is a front elevational view of the fuselage-retaining assemblyof FIG. 8E.

FIG. 8G is a back elevational view of the fuselage-retaining assembly ofFIG. 8E.

FIG. 8H is a top perspective view of the rotor arm module and rearlanding gear module storage device of the present disclosure.

FIG. 8I is a cross-sectional view of the rotor arm module and rearlanding gear module storage device of FIG. 8H taken substantially alongline 8I-8I of FIG. 8H.

FIG. 8J is a top perspective view of the hub module storage tray of thepresent disclosure.

FIG. 9A is a top perspective view of one example embodiment of theanchor system of the present disclosure.

FIG. 9B is a partially exploded top perspective view of the anchorsystem of FIG. 9A.

FIG. 9C is an exploded top perspective view of the breakaway device ofthe anchor system of FIG. 9A.

FIG. 9D is a top perspective view of the anchor system of FIG. 9A storedwithin a storage container along with other accessories.

FIG. 10A is a partial cross-sectional view of the saddle of FIG. 4Ashowing the cam in an attached rotational position and a hook of thefixed-wing aircraft attached taken substantially along line 10A-10A ofFIG. 4C.

FIG. 10B is a partial cross-sectional view of the saddle of FIG. 4Ashowing the cam halfway between the attached rotational position and thedetached rotational position and the hook of the fixed-wing aircraftbeing pushed off of the cam taken substantially along line 10A-10A ofFIG. 4C.

FIG. 10C is a partial cross-sectional view of the saddle of FIG. 4Ashowing the cam in the detached rotational position and the hook of thefixed-wing aircraft detached from the cam taken substantially along line10A-10A of FIG. 4C.

FIG. 10D is a diagrammatic view of the multicopter of FIG. 1A, thefixed-wing aircraft, the flexible capture member of the presentdisclosure, the breakaway device of FIG. 9C, and the flexible capturemember payout and retract device of the anchor system of FIG. 9A justbefore capture.

FIG. 10E is a cross-sectional view of the breakaway device of FIG. 9Cwhen the compression spring is fully extended taken substantially alonga plane through the longitudinal axis of the breakaway device.

FIG. 10F is a cross-sectional view of the breakaway device of FIG. 9Cwhen the compression spring is fully compressed and the finger beginningto rotate out of the breakaway sleeve taken substantially along a planethrough the longitudinal axis of the breakaway device.

FIG. 10G is a cross-sectional view of the breakaway device of FIG. 9Cwhen the compression spring is fully compressed and the finger hasrotated out of the breakaway sleeve taken substantially along a planethrough the longitudinal axis of the breakaway device.

FIG. 10H is a diagrammatic view of the multicopter of FIG. 1A, thefixed-wing aircraft, the flexible capture member of the presentdisclosure, the breakaway device of FIG. 9C, and the flexible capturemember payout and retract device of the anchor system of FIG. 9A justafter capture when the anchor system is paying out flexible capturemember.

FIG. 10I is a diagrammatic view of the multicopter of FIG. 1A, thefixed-wing aircraft, the flexible capture member of the presentdisclosure, the breakaway device of FIG. 9C, and the flexible capturemember payout and retract device of the anchor system of FIG. 9A afterthe fixed-wing aircraft has stopped moving and the anchor system hasretracted the paid-out portion of the flexible capture member.

DETAILED DESCRIPTION

While the features, methods, devices, and systems described herein maybe embodied in various forms, there are shown in the drawings, and willhereinafter be described, some exemplary and non-limiting embodiments.Not all of the depicted components described in this disclosure may berequired, however, and some implementations may include additional,different, or fewer components from those expressly described in thisdisclosure. Variations in the arrangement and type of the components;the shapes, sizes, and materials of the components; and the manners ofattachment and connections of the components may be made withoutdeparting from the spirit or scope of the claims as set forth herein.Also, unless otherwise indicated, any directions referred to hereinreflect the orientations of the components shown in the correspondingdrawings and do not limit the scope of the present disclosure. Thisspecification is intended to be taken as a whole and interpreted inaccordance with the principles of the invention as taught herein andunderstood by one of ordinary skill in the art.

The rotorcraft-assisted launch and retrieval system of variousembodiments of the present disclosure generally includes: (1) aneight-rotor modular multicopter 10 attachable to (and detachable from) afixed-wing aircraft 20 to facilitate launch of the fixed-wing aircraft20 into wing-borne flight; (2) a storage and launch system 2000 usableto store the modular multicopter 10 and to facilitate launch of thefixed-wing aircraft 20 into wing-borne flight; and (3) an anchor system3000 usable (along with the multicopter 10 and a flexible capture member5000) to retrieve the fixed-wing aircraft 20 from wing-borne flight.

Generally, to launch the fixed-wing aircraft 20 into wing-borne flight,an operator (or operators): (1) removes the disassembled multicopter 10from a container of the storage and launch system 2000; (2) assemblesthe multicopter 10; (3) mounts the fixed-wing aircraft 20 to alaunch-assist assembly of the storage and launch system 2000; (4)attaches the fixed-wing aircraft 20 to the multicopter 10; (5) remotelycontrols the multicopter 10 to lift the fixed-wing aircraft 20 to adesired altitude and to accelerate the fixed-wing aircraft 20 to adesired speed; and (6) remotely causes the fixed-wing aircraft 20 todetach from the multicopter 10, thereby releasing the fixed-wingaircraft 20 into wing-borne flight.

Generally, to retrieve the fixed-wing aircraft 20 from wing-borneflight, the operator (or operators): (1) attaches one end of a flexiblecapture member 5000 to the multicopter 10 and the other end to theanchor system 3000; (2) remotely controls the multicopter 10 to flyabove the anchor system 3000 until the flexible capture member 5000 istensioned to a designated level; and (3) controls the fixed-wingaircraft 20 to capture the flexible capture member 5000.

The components of one example embodiment of the multicopter 10, thestorage and launch system 2000, and the anchor system 3000 are describedbelow in connection with FIGS. 1A to 9D, followed by a detaileddescription of example methods for launching and retrieving thefixed-wing aircraft 20 into and from wing-borne flight using themulticopter 10, the storage and launch system 2000, and the anchorsystem 3000 in connection with FIGS. 10A to 10I.

The example embodiment of the systems and methods of the presentdisclosure shown in the drawings and described below include amulticopter. In other embodiments, the rotorcraft may include anysuitable quantity of rotors (e.g., be a helicopter or a quadcopter).

1. Multicopter Components

FIGS. 1A, 1B, 1C, 1D, 1E, 1F, and 1G show the multicopter 10. Themulticopter 10 is modular in that it is assembled from (and can bedisassembled into) a plurality of different modules or subassemblies.The multicopter is removably attachable to: (1) the fixed-wing aircraft20 to facilitate launch of the fixed-wing aircraft 20 into wing-borneflight, and (2) the flexible capture member 5000 to facilitate retrievalof the fixed-wing aircraft 20 from wing-borne flight.

As best shown in FIGS. 1E and 1F, the multicopter 10 includes thefollowing 13 modules or subassemblies: a hub module 100; first, second,third, and fourth rotor arm modules 400 a, 400 b, 400 c, and 400 d;first and second front landing gear extension modules 500 a and 500 b;first and second rear landing gear extension modules 500 c and 500 d;first and second front landing gear modules 600 a and 600 b; and firstand second rear landing gear modules 600 c and 600 d.

As described in detail below, to assemble the multicopter 10 from these13 modules or subassemblies, after removing the 13 modules from thecontainer of the storage and launch system 2000, an operator: (1)attaches the first, second, third, and fourth rotor arm modules 400 a,400 b, 400 c, and 400 d to the hub module 100; (2) attaches the firstand second front landing gear extension modules 500 a and 500 b to thefirst and second rotor arm modules 400 a and 400 b, respectively; (3)attaches the first and second rear landing gear extension modules 500 cand 500 d to the third and fourth rotor arm modules 400 c and 400 d,respectively; (4) attaches the first and second front landing gearmodule 600 a and 600 b to the first and second front landing gearextension modules 500 a and 500 b, respectively; and (5) attaches thefirst and second rear landing gear module 600 c and 600 d to the firstand second rear landing gear extension modules 500 c and 500 d,respectively.

The modularity of this multicopter is beneficial compared to non-modularor unitary multicopter construction. First, the modularity of thismulticopter enables an operator to quickly and easily disassemble thisrelatively large multicopter into 13 smaller modules or subassemblies.The operator can compactly store these modules or subassemblies in asingle container, which makes the disassembled multicopter easy to storeand transport compared to the assembled multicopter. Second, if a partof this multicopter breaks, its modularity enables the operator toquickly and easily replace the module(s) or subassembly(ies) includingthe broken part with a properly functioning replacement module(s) orsubassembly(ies) rather than waste time repairing the brokencomponent(s).

FIG. 1G is a block diagram of certain electrically controlled componentsof the multicopter 10. In this embodiment, although not shown in FIG.1G, four lithium-ion batteries power these components (as describedbelow).

The hub module 100 includes: (1) an autopilot or controller 272; (2) atelemetry link 274; (3) an R/C receiver 276; (4) a GPS antenna 285; (5)eight electronic speed controllers (ESCs) 265 a, 265 b, 265 c, 265 d,265 e, 265 f, 265 g, and 265 h; (6) a cam servo motor 381; and (7) alock servo motor 391. The first rotor arm module 400 a includes an upperrotor motor 465 a and a lower rotor motor 465 b. The second rotor armmodule 400 b includes an upper rotor motor 465 c and a lower rotor motor465 d. The third rotor arm module 400 c includes an upper rotor motor465 e and a lower rotor motor 465 f. The fourth rotor arm module 400 dincludes an upper rotor motor 465 g and a lower rotor motor 465 h.

The autopilot 272 is electrically connected to the telemetry link 274,the R/C receiver 276, the GPS antenna 285, and the ESCs 265 a to 265 h.The R/C receiver 276 is electrically connected to the cam servo motor381 and the lock servo motor 391 and is wirelessly connectable to an R/Ccontroller (not shown).

The GPS antenna 285 is wirelessly connectable or otherwise configured tocommunicate with to a variety of GPS satellite constellations (notshown).

The ESC 265 a is electrically connected to and, along with the autopilot272, controls the operation of the upper rotor motor 465 a of the firstrotor arm module 400 a. The ESC 265 b is electrically connected to and,along with the autopilot 272, controls the operation of the lower rotormotor 465 b of the first rotor arm module 400 a. The ESC 265 c iselectrically connected to and, along with the autopilot 272, controlsthe operation of the upper rotor motor 465 c of the second rotor armmodule 400 b. The ESC 265 d is electrically connected to and, along withthe autopilot 272, controls the operation of the lower rotor motor 465 dof the second rotor arm module 400 b. The ESC 265 e is electricallyconnected to and, along with the autopilot 272, controls the operationof the upper rotor motor 465 e of the third rotor arm module 400 c. TheESC 265 f is electrically connected to and, along with the autopilot272, controls the operation of the lower rotor motor 465 f of the thirdrotor arm module 400 c. The ESC 265 g is electrically connected to and,along with the autopilot 272, controls the operation of the upper rotormotor 465 g of the fourth rotor arm module 400 d. The ESC 265 h iselectrically connected to and, along with the autopilot 272, controlsthe operation of the lower rotor motor 465 h of the fourth rotor armmodule 400 d.

The R/C receiver 276 is configured to receive control signals from theR/C controller (not shown), which the operator of the multicopter 10controls. These control signals may be associated with movement of themulticopter 10—in which case the R/C receiver 276 is configured totransmit the control signals to the autopilot 272—or operation of thecam servo motor 381 or the lock servo motor 391—in which case the R/Creceiver 276 is configured to transmit the control signals to the camservo motor 381 or the lock servo motor 391 (as appropriate).

The GPS antenna 285 is configured to receive signals from one of the GPSsatellite constellations, to determine multicopter location informationusing those signals, and to transmit the multicopter locationinformation to the autopilot 272.

The autopilot 272 and the ESCs 265 a to 265 h control operation of therotor motors 465 a to 465 h based on the received control signals and/ormulticopter location data. Specifically, the autopilot 272 receives thecontrol signals and the multicopter location information and determines,based on this data, how to control the rotor motors in response. Theautopilot 272 determines appropriate rotor motor control signals andtransmits the rotor motor control signals to one or more of the ESCs 265a to 265 h, which causes the ESC(s) to control its (their) correspondingrotor motor(s) accordingly.

A computing device (such as laptop computer, tablet computer, or mobilephone, not shown) is wirelessly connectable to the autopilot 272 via thetelemetry link 274. Once the autopilot 272 establishes a connection withthe computing device through the telemetry link 274, the autopilot 272can share information associated with the operation of the multicopter10 (such as the operational status of the multicopter 10, GPScoordinates of the multicopter 10, rotor motor status, and the like)with the computing device.

Each module or subassembly of the multicopter 10 is described in furtherdetail below.

1.1 Hub Module

FIGS. 2A, 2B, and 2C show the hub module 100. The hub module 100: (1)serves as the attachment point for the rotor arm modules 400 a to 400 d;(2) is the portion of the multicopter 10 to which the fixed-wingaircraft 20 is attached for launch; (3) is the portion of themulticopter 10 to which the flexible capture member 5000 is attached forretrieval of the fixed-wing aircraft 20; (4) includes the power sourcefor the multicopter 10; and (5) includes certain components used tocontrol operation of the multicopter 10.

As best shown in FIG. 2C, the hub module 100 includes a hub base 200 anda saddle 300. The saddle 300 is attached to the underside of the hubbase 200 via two brackets 120 a and 120 b and four struts 110 a, 110 b,110 c, and 110 d. Each strut 110 is attached at one end to the hub base200 and at the other end to the saddle 300. This is merely one exampleof how the saddle can be attached to the hub base, and in otherembodiments the saddle may be attached to the hub base in any suitablemanner. For instance, in another embodiment, rather than being attachedto the hub base, each strut is attached to a different rotor arm module,such as to one of the rotor motor assemblies of the rotor arm modules.

1.1.1 Hub Base

FIGS. 3A, 3B, 3C, 3D, 3E, 3F, 3G, and 3H show the hub base 200 orcomponents thereof. The hub base 200 is the portion of the hub module100 that: (1) serves as the attachment point for the rotor arm modules400 a to 400 d; (2) includes the power source for the multicopter 10;and (3) includes certain components used to control operation of themulticopter 10.

As best shown in FIGS. 3C and 3D, the hub base 200 includes two hollowelongated rectangular supports 210 a and 210 b. The hollow supports 210a and 210 b interlock with one another near their centers such that thehollow supports 210 a and 210 b are oriented transversely (such asgenerally perpendicularly) to one another and generally form a crossshape when viewed from above or below. Reinforcing plugs 212 aredisposed within the hollow supports 210 a and 210 b such that fastenerreceiving openings (not labeled) of the reinforcing plugs 212 verticallyalign with fastener receiving openings (not labeled) of the hollowsupports 210 a and 210 b. Upper and lower braces 220 a and 220 bsandwich the hollow supports 210 a and 210 b. A fastener 222 threadedthrough the upper brace 220 a, the hollow support 210 a, the reinforcingplug 212, the hollow support 210 b, and the lower brace 220 b holds theupper and lower braces 220 a and 220 b and the hollow supports 210 a and210 b together. This ensures the hollow supports 210 a and 210 b remaininterlocked and ensures their orientation with respect to one anotherdoes not substantially change.

The hollow supports 210 a and 210 b are attached to a hub base plate 202via suitable fasteners (not labeled) threaded through the hollowsupports 210 a and 210 b and the reinforcing plugs 212 disposed withinthe hollow supports 210 a and 210 b. As best shown in FIG. 3B, twostabilizers 290 a and 290 b are attached to and extend downward fromeither hollow support 210 a and 210 b. The free ends of the stabilizers290 a and 290 b terminate in feet configured to contact the fixed-wingaircraft 20 to help prevent the fixed-wing aircraft 20 from rotatingabout its roll axis relative to the multicopter 10. The feet areadjustable in length (e.g., are threaded such that they can be shortenedby threading further into the stabilizers or lengthened by unthreadingfurther out of the stabilizers).

As best shown in FIG. 3C, first and third isolator plate mounts 240 aand 240 c are attached (such as via lashing) to the hollow support 210 aand second and fourth isolator plate mounts 240 b and 240 d are attached(such as via lashing) to the hollow support 210 b radially inward of theends of the hollow supports 210 a and 210 b. Each isolator plate mount240 includes a first isolator plate mounting post 242 defining athreaded fastener receiving opening at least partially therethrough anda second isolator plate mounting post 244 defining a threaded fastenerreceiving opening at least partially therethrough.

An isolator plate 250 is slidably mounted to the isolator plate mounts240 a, 240 b, 240 c, and 240 d. FIGS. 3E and 3F show how the isolatorplate 250 is mounted to the isolator plate mount 240 b. For simplicityand brevity, illustrations of how the isolator plate 250 is mounted tothe remaining three isolator plate mounts 240 a, 240 c, and 240 d in asimilar manner are not provided.

The isolator plate 250 defines first and second mounting openings 250 aand 250 b therethrough. An elastomeric grommet 252 is installed in thefirst mounting opening 250 a of the isolator plate 250. The grommet 252defines a first isolator plate mounting post receiving channel 252 atherethrough, and the first isolator plate mounting post 242 b isslidably received in the first isolator plate mounting post receivingchannel 252 a. A fastener 254 having a stop washer 254 a beneath itshead is partially threaded into the fastener receiving opening of thefirst isolator plate mounting post 242 b. Upper and lower conicalsprings 256 a and 256 b—held in place by a fastener 258 partiallythreaded into the fastener receiving opening of the second isolatorplate mounting post 244 b—sandwich the isolator plate 250.

The hollow support 210 b and the stop washer 254 a constrain thevertical movement of the isolator plate 250. In other words, theisolator plate 250 can move vertically between a lower position in whichthe grommet 252 contacts the hollow support 210 b and an upper positionin which the grommet 252 contacts the stop washer 254 a. The conicalsprings 256 a and 256 b act as a suspension that absorbs (or partiallyabsorbs) vibrations of the hollow support 210 b that would otherwise bedirectly transferred to the isolator plate 250, which could affectoperation of certain components of the multicopter 10 (such as theautopilot 272).

The relatively high mass of the batteries 260 a to 260 d and the factthat they are mounted to the isolator plate 250 and close-coupled to theautopilot 272 (which includes an inertial measurement unit (IMU)) workswith the suspension to help prevent undesired vibration of the isolatorplate 250 and therefore the autopilot 272. In certain embodiments, torthe autopilot 272 to perform well, the IMU must resolve accelerations onthe order of 0.1 gee and rotations of 0.1 radians/second. In variousembodiments, the autopilot 272 cannot do this reliably when (˜10-gee)vibration, caused by rotor unbalance, for example, is transmitted fromthe airframe of the multicopter 10 to the IMU. When the mass of thebatteries 260 a to 260 d is used to ballast the IMU on the isolatorplate 250, and the isolator plate 250 is anchored to the airframestructure through the suspension, the IMU enjoys the vibration-freemounting location. By mounting the isolator plate 250 well-outboard atits corners, the IMU remains sufficiently well-coupled to the airframethat pitch and roll movements are transmitted to the IMU, which is ableto effectively resolve these motions.

As best shown in FIGS. 3A and 3B, The following components are mountedto the isolation plate 250: (1) the batteries 260 a, 260 b, 260 c, and260 d (which are received in respective battery receivers (not labeled)configured to retain the batteries and to electrically connect thebatteries to components of the multicopter to power those components);(2) the ESCs 265 a to 265 h; (3) an avionics enclosure 270 that houses avariety of components including the autopilot 272, the telemetry link274, and the R/C receiver 276; (4) a GPS antenna mounting bracket 280 onwhich the GPS antenna 285 is mounted; (5) navigation lights (not shown);and (6) a Mode C transponder (not shown).

The four open ends of the hollow supports 210 a and 210 b form rotor armmodule receiving sockets that can receive one of the rotor arm modules400 a to 400 d. Specifically, the hollow support 210 a forms a firstrotor arm module receiving socket 214 a and a third rotor arm modulereceiving socket (not shown) and the hollow support 210 b forms a secondrotor arm module receiving socket 214 b and a fourth rotor arm modulereceiving socket (not shown).

As best shown in FIG. 3A, female blind mate assemblies 230 are attachedto the ends of the hollow supports 210 a and 210 b. Specifically, afirst female blind mate assembly 230 a is attached to one end of thehollow support 210 a near the first rotor arm module receiving socket214 a, a second female blind mate assembly 230 b is attached to one endof the hollow support 210 b near the second rotor arm module receivingsocket 214 b, a third female blind mate assembly 230 c is attached tothe other end of the hollow support 210 a near the third rotor armmodule receiving socket 214 c, and a fourth female blind mate assembly230 d is attached to the other end of the hollow support 210 b near thefourth rotor arm module receiving socket 214 d.

The female blind mate assemblies 230 (along with the corresponding maleblind mate connectors described below with respect to the rotor armmodules) facilitate: (1) mechanical attachment of the rotor arm modules400 a, 400 b, 400 c, and 400 d to the hub module 100; (2) power flowfrom the battery(ies) 260 a, 260 b, 260 c, and/or 260 d to the rotormotors 465 a to 465 h of the rotor arm modules 400 a, 400 b, 400 c, and400 d; and (3) communication between the ESCs 265 a to 265 h and therotor motors 465 a to 465 h.

FIGS. 3G and 3H show the second female blind mate assembly 230 b. Thefemale blind mate assemblies 230 a, 230 c, and 230 d are similar to thesecond female blind mate assembly 230 b and are not separately shown ordescribed for brevity.

The second female blind mate assembly 230 b includes: (1) a female blindmate connector 231 b including a plurality of pin receptacles (notlabeled); (2) three elastomeric grommets 232 b; (3) three rigid, hollowcylindrical spacers 233 b; (4) three fasteners 234 b; (5) three nuts 235b; (6) a mounting bracket 236 b; and (7) mounting bracket fasteners (notlabeled).

Although not shown for clarity, the female blind mate connector 231 band, particularly, the pin receptacles, are electrically connected tothe corresponding ESCs 265 c and 265 d via wiring. In this exampleembodiment, the female blind mate connector 231 b includes 12 pinreceptacles, six of which are connected to the ESC 265 c via wiring andthe other six of which are connected to the ESC 265 d via wiring.

The mounting bracket 236 b is positioned at a desired location along thehollow support 210 b, and the mounting bracket fasteners are tightenedto clamp the mounting bracket 236 b in place relative to the hollowsupport 210 b.

The female blind mate connector 231 b is flexurally mounted to themounting bracket 236 b via the elastomeric grommets 232 b, the spacers233 b, the fasteners 234 b, and the nuts 235 b. Specifically, theelastomeric grommets 232 b are fitted into corresponding cavities in thefemale blind mate connector 231 b. As best shown in FIG. 3H, each cavityincludes an inwardly projecting annular rib that fits into acorresponding annular cutout of the corresponding elastomeric grommet232 b. The spacers 233 b are disposed within longitudinal bores definedthrough the elastomeric grommets 232 b. The fasteners 234 b extendthrough the hollow spacers 233 b and through corresponding fastenerreceiving openings defined through the mounting bracket 236 b into theircorresponding nuts 235 b. This secures the female blind mate connector231 b to the mounting bracket 236 b.

This flexural mount of the female blind mate connector to the mountingbracket via the elastomeric grommets is beneficial compared to a rigidconnection of the female blind mate connector to the mounting bracket.The flexural mount enables the female blind mate connector to move—viadeformation of the elastomeric grommet—relative to the mounting bracket(and the rest of the hub module) when loads are applied to the femaleblind mate connector, such as loads imposed on the female blind mateconnector by the attached rotor arm module during flight. Because thefemale blind mate connector is not rigidly attached to the correspondingmounting bracket, it is less likely that the pins of the male blind mateconnector (described below) received by the pin receptacles of thefemale blind mate connector will lose electrical contact—causing themulticopter 10 to lose control of at least one of its rotor motors—whenloads are applied to the female blind mate connector.

As best shown in FIG. 3H, a latch plate 237 is attached to the undersideof each hollow support 210 a and 210 b below each female blind mateconnector 231 attached thereto. The latch plate 237 includes a clawengager 238 and a backstop 239. The latch plate 237 is described belowwith respect to the locking assemblies 420 of the rotor arm modules 400a to 400 d.

In some embodiments, the hub module (either the hub base, the saddle, orboth) or other elements of the multicopter include ballast to obtain adesired weight distribution and/or provide stability during flight.

1.1.2 Saddle

FIGS. 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4I, and 4J show the saddle 300 orcomponents thereof. The saddle 300 is the portion of the hub module 100:(1) to which the fixed-wing aircraft 20 is attached for launch; (2) fromwhich the fixed-wing aircraft 20 is detached for launch; and (3) towhich the flexible capture member 5000 is attached for retrieval of thefixed-wing aircraft 20. The saddle 300 also enables the operator to varythe pitch angle of the fixed-wing aircraft 20 relative to themulticopter 10.

As best shown in FIG. 4C, the saddle 300 includes a saddle base bracket310 and first and second saddle side plates 320 a and 320 b. The firstand second saddle side plates 320 a and 320 b are pivotably connected toopposite sides of the saddle base bracket 310 near the front end of thesaddle base bracket 310. The first and second saddle side plates 320 aand 320 b are also attached to opposite sides of the saddle base bracket310 near the rear end of the saddle base bracket 310 via locking devices322 a and 322 b (which are cam lever locks in this example embodimentbut can be any suitable locking devices). The locking devices 322 a and322 b extend through respective slots 321 a and 322 b defined throughthe respective first and second side plates 320 a and 320 b.

As shown in FIGS. 4D and 4E, the orientation of the slots 321 a and 321b enables an operator to vary the angle α formed between a planeincluding the tops of the first and second saddle side plates 320 a and320 b—to which the hub base 200 is attached—and a plane including thegenerally horizontally extending bottom portion of the saddle base plate310. Plane as used herein can mean either a physical plane or a virtualreference plane. The angle α generally corresponds to the angle formedbetween the hub base plate 202 of the hub base 200 and the fuselage ofthe fixed-wing aircraft 20 when the fixed-wing aircraft 20 is attachedto the saddle 300. To change the angle α, the operator unlocks thelocking devices 322 a and 322 b, rotates the first and second sideplates 320 a and 320 b relative to the saddle base bracket 310 aroundtheir pivotable attachments to the saddle base bracket 310 to thedesired rotational position (or vice-versa), and re-locks the lockingdevices 322 a and 322 b. In this example embodiment, the angle α isvariable from about 0 degrees to about 10 degrees, though in otherembodiments the angle α is variable between any suitable angles.

In certain embodiments, an operator can cause the first and second sideplates to rotate relative to the saddle while the multicopter 10 isflying. For instance, the operator may desire to release the fixed-wingaircraft nose-down from a hover. Conversely, the operator may desire torelease the fixed-wing aircraft nose-up (such as nose-up about 10degrees) to facilitate launch while the multicopter is dashing forward(this nose-up pitch reduces wind drag and better-aligns the thrustvector of the fixed-wing aircraft with the desired direction of travel).The multicopter may include any suitable combination of elements tofacilitate this remote pivoting, such as various motors, actuators, andthe like.

As best shown in FIGS. 4A, 4B, and 4C, a stabilizing bracket 330 isattached to the first and second saddle side plates 320 a and 320 b andextends across the space between the first and second saddle side plates320 a and 320 b. A downwardly curved front aircraft engaging bracket 340a is attached to the underside of the saddle base bracket 310 near thefront of the saddle base bracket 310. A downwardly curved rear aircraftengaging bracket 340 b is attached to the underside of the saddle basebracket 310 near the rear of the saddle base bracket 310.

As best shown in FIG. 4C, a cam 350 is rotatably attached to and extendsacross the width of the saddle base bracket 310 such that the cam 350 istransverse (such as generally perpendicular) to the first and secondsaddle side plates 320 a and 320 b. As best shown in FIGS. 4F, 4H, and4I, the portion of the cam 350 near its longitudinal center has anirregularly shaped profile including a first relatively wide ridge 351,a second relatively narrow ridge 353, and a valley 352 between the firstand second ridges 351 and 353. This irregularly shaped profilefacilitates attaching the fixed-wing aircraft 20 to the cam 350 (andtherefore to the multicopter 10) and detaching the fixed-wing aircraft20 from the cam 350 (and therefore from the multicopter 10), asdescribed below with respect to FIGS. 10A, 10B, and 10C. The cam 350also includes a cam control arm 354 and a foot 355 extendingtransversely (such as generally perpendicularly) from the longitudinalaxis of the cam 350.

An aircraft attaching/detaching assembly 380 attached to the saddle basebracket 310 controls rotation of the cam 350 relative to the saddle basebracket 310. As best shown in FIG. 4G, the aircraft attaching/detachingassembly 380 includes: (1) a cam servo motor 381 having a cam servomotor shaft 381 a; (2) a cam servo motor arm 382; (3) a cam servo motorarm lock device 382 a; (4) upper and lower servo spacers 383 a and 383b; (5) upper and lower nut plates 384 a and 384 b; (6) fasteners 385;(7) a cam rotation control link 386 having connectors 386 a and 386 b ateither end; (8) a lock servo motor 391 having a lock servo motor shaft391 a; and (9) a lock servo motor arm 392 terminating at one end in alock servo motor locking extension 392 a.

The cam servo motor 381 and the lock servo motor 391 are attached to oneanother and to the saddle base bracket 310 via the fasteners 385, theupper and lower servo spacers 383 a and 383 b, and the upper and lowernut plates 384 a and 384 b. The cam servo motor arm 382 is attached nearone end to the cam servo motor shaft 381 a and near the other end to theconnector 386 a. The connector 386 b is attached to the cam control arm354 of the cam 350, which links the cam servo motor shaft 381 a to thecam 350. The cam servo motor arm lock device 382 a is attached to thecam servo motor arm 382 between the connector 386 a and the cam servomotor shaft 381 a. The lock servo motor arm 392 is attached to the lockservo motor shaft 391 a. The rearwardly extending portion of the lockservo motor arm 392 terminates in the lock servo motor locking extension392 a, which is engageable to the cam servo motor arm lock device 382 ain certain instances.

The cam servo motor 381 controls rotation of the cam 350 relative to thesaddle base bracket 310. To rotate the cam 350, the cam servo motor 381rotates the cam servo motor shaft 381 a, which rotates the attached camservo arm 382, which in turn rotates the cam 350 via the cam rotationcontrol link 386. The cam servo motor 381 can rotate the cam 350 from anattached rotational position—shown in FIG. 4H—to a detached rotationalposition—shown in FIG. 4I (and vice-versa).

The lock servo motor 391 controls rotation of the lock servo arm 392between a cam rotation-preventing rotational position—shown in FIG.4H—and a cam rotation-enabling rotational position—shown in FIG. 4I (andvice-versa). When the cam 350 is in the attached rotational position andthe lock servo arm 392 is in the cam rotation-preventing rotationalposition, the lock servo motor locking extension 392 a engages the camservo motor arm lock device 382 a of the cam servo motor arm 382. Thisprevents the cam servo motor 381 from rotating the cam 350 from theattached rotational position to the detached rotational position.

FIGS. 4H and 4I show how the cam servo motor 381 and the lock servomotor 391 operate to rotate the cam 350 from the attached rotationalposition to the detached rotational position. Initially, the cam servomotor 381 is in the attached rotational position and the lock servomotor 391 is in the cam rotation-preventing rotational position. Here,the lock servo motor locking extension 392 a on the end of the lockservo arm 392 engages the cam servo motor arm lock device 382 a of thecam servo motor arm 382.

Since the lock servo motor locking extension 392 a is engaged to the camservo motor arm lock device 382 a of the cam servo motor arm 382, thecam servo motor 381 cannot rotate the cam 350 from the attachedrotational position to the detached rotational position(counter-clockwise from this viewpoint).

Rotating the cam 350 from the attached rotational position to thedetached rotational position is a two-step process. The operator firstoperates the lock servo motor 391 to rotate the lock servo motor arm 392into the cam rotation-enabling rotational position (counter-clockwisefrom this viewpoint). Second, the operator operates the cam servo motor381 to rotate the cam 350 from the attached rotational position to thedetached rotational position (counter-clockwise from this viewpoint).

FIGS. 10A to 10C, described below, show how rotation of the cam from theattached rotational position to the detached rotational position causesthe fixed-wing aircraft to detach from the cam.

The foot 355 controls the extent to which the cam 350 can rotate. Thefoot 355 is oriented such that when the cam 350 rotates a certain amountin a first direction relative to the saddle base bracket 310, the foot355 contacts the saddle base bracket 310 and prevents the cam 350 fromrotating any further in that first direction. Similarly, when the cam350 rotates a particular amount in a second opposite direction relativeto the saddle base bracket 310, the foot 355 contacts the saddle basebracket 310 and prevents the cam 350 from rotating any further in thatsecond direction. The foot 355 is angled to stop the cam 350 fromrotating before it exerts an undue force on the cam rotation controllink 386, and by extension the cam motor arm 382 and the cam motor shaft381 a.

1.2 Rotor Arm Modules

The rotor arm modules 400 a to 400 d are mechanically attachable to andmechanically lockable to the hub module 200 and include: (1) the eightrotors of the multicopter 10; (2) the eight rotor motors that drivethese rotors; (3) gear reduction trains that couple the rotor motors totheir corresponding rotors; and (4) locking assemblies that lock therotor arm modules 400 a to 400 d to the hub module 100.

FIGS. 5A, 5B, 5C, 5D, 5E, 5F, 5G, 5H, 5I, and 5J show the first rotorarm module 400 a or components thereof. The other rotor arm modules 400b, 400 c, and 400 d are similar to the first rotor arm module 400 a andare not separately shown or described for brevity.

As best shown in FIGS. 5A, 5B, 5H, and 5J, the first rotor arm module400 a includes: (1) a generally rectangular hollow elongated rotor arm410 a; (2) a generally rectangular hollow rotor arm extension 410 b; (3)a locking assembly 420; (4) a male blind mate connector 431; (5) upperand lower rotor motor assemblies 460 a and 460 b; and (6) a rotorassembly 470.

The rotor arm extension 410 b is attached to the rotor arm 410 a suchthat part of the rotor arm extension 410 b is disposed within the rotorarm 410 a and the remainder of the rotor arm extension 410 b extendsfrom the rotor arm 410 a. The locking assembly 420 is attached to theunderside of the rotor arm 410 a near the end of the rotor arm 410 afrom which the rotor arm extension 410 b extends. The male blind mateconnector 431 is attached to the end of the rotor arm 410 a from whichthe rotor arm extension 410 b extends. The upper and lower rotor motorassemblies 460 a and 460 b and the rotor assembly 470 are attached tothe rotor arm 410 a in a manner described in detail below.

Although not shown, the open end of the rotor arm 410 a opposite the endfrom which the rotor arm extension 410 b extends forms a first frontlanding gear extension module receiving socket that can receive thefirst front landing gear extension module 500 a, as described below.

As best shown in FIGS. 5A, 5B, 5C, 5D, 5E, and 5F, the male blind mateconnector 431—along with its counterpart female blind mate connector 231a of the hub module 100—facilitate: (1) mechanical attachment of thefirst rotor arm module 400 a to the hub module 100; (2) electrical powerflow from the battery(ies) 260 a, 260 b, 260 c, and/or 260 d to theupper and lower rotor motors 465 a and 465 b of the first rotor armmodule 400 a; and (3) communication between the ESCs 265 a and 265 btheir corresponding upper and lower rotor motors 465 a and 465 b.

The male blind mate connector 431 includes a plurality of pins 431 aconfigured to mate with the pin receptacles of the female blind mateconnector 231 a. Although not shown for clarity, the male blind mateconnector 431 and, particularly, the pins 431 a, are electricallyconnected to the corresponding upper and lower rotor motors 465 a and465 b via wiring. In this example embodiment, the male blind mateconnector 431 includes 12 pins 431 a, six of which are electricallyconnected to the upper rotor motor 465 a via wiring and the other six ofwhich are electrically connected to the lower rotor motor 465 b viawiring. In this example embodiment, each motor only requires three motorleads to properly function, but the multicopter 10 includes two motorleads for each motor pole. By using two motor leads per motor pole, themulticopter 10 eliminates single-point failures (i.e., both leads wouldhave to fail rather than just a single lead for the motor to fail).

To attach the rotor arm module 400 a to the hub module 100, an operatorinserts the rotor arm extension 410 b into the first rotor arm modulereceiving socket 214 of the hub module 100 and slides the rotor armmodule 400 a toward the hub module 100 with enough force to mate thepins of the male blind mate connector 431 with the pin receptacles ofthe female blind mate connector 231 a of the hub module 100.

In an alternative embodiment, rather than the hub module slidablyreceiving a portion of the rotor arm module to attach the rotor armmodule to the hub module, the rotor arm module slidably receives acomponent (such as an arm) of the hub module to attach the rotor armmodule to the hub module.

As best shown in FIGS. 5C, 5D, 5E, and 5F, the locking assembly 420includes a drawcatch 420 a and a drawcatch lock 420 b that: (1)facilitate attaching the first rotor arm module 400 a to the hub module100; (2) lock the first rotor arm module 400 a to the hub module 100;and (3) facilitate detachment of the first rotor arm module 400 a fromthe hub module 100.

As best shown in FIG. 5C, the drawcatch 420 a includes: (1) a base 421;(2) a lever 422; (3) a claw 423; (4) a first fastener 424 (such as aclevis pin or other suitable fastener); and (5) a second fastener 425(such as a clevis pin or other suitable fastener).

The drawcatch lock 420 b includes: (1) a base 426; (2) a lock/releasedevice 427 having a locking shelf 427 a; (3) a pin 428 (or othersuitable connector); and (4) a compression spring 429 (or other suitablebiasing element).

The base 421 is attached to the underside of the rotor arm 410 a. Thelever 422 is pivotably connected at one end to the base 421 via thefirst fastener 424. The other end of the lever 422 includes a handle 422a. The claw 423 is pivotably connected at one end to the lever 422 viathe second fastener 425. The other end of the claw includes a latchplate engager 423 a.

The base 426 is attached to the underside of the rotor arm 410 a. Thelock/release device 427 is pivotably connected to the base 426 via thepin 428. The compression spring 429 is disposed between the base 426 andthe lock/release device 427 and retained in place via cavities and/orprojections defined in or extending from these components (not shown).

The lock/release device 427 is rotatable about the pin 428 from a lockrotational position to a release rotational position. The compressionspring 429 biases the lock/release device 427 to the lock rotationalposition. To rotate the lock/release device 427 from the lock rotationalposition to the release rotational position, the operator pushes thelock/release device 427 inward with enough force to overcome thespring-biasing force and compress the compression spring 429.

The operator uses the locking assembly 420 to lock the male blind mateconnector 431 with the female blind mate connector 231 a as follows. Theoperator rotates the handle 422 a of the lever 422 around the firstfastener 424 toward the latch plate 237 on the hollow support 210 a ofthe hub module 100 and engages the claw engager 238 of the latch plate237 with the latch plate engager 423 a of the claw 423. The operatorthen rotates the handle 422 a around the first fastener 424 and towardthe lock/release device 427 until the handle 422 a contacts thelock/release device 427. Continued rotation of the lever 422 forces thelock/release device 427 inward, which overcomes the spring-biasing forceand begins compressing the compression spring 429. This causes thelock/release device 427 to being rotating to the release rotationalposition. Once the handle 422 rotates past the locking shelf 427 a, thespring-biasing force of the compression spring 429 causes thelock/release device 427 to rotate back to the lock rotational position.At this point, the locking shelf 427 a prevents the handle 422 fromrotating back toward the latch plate 237, and the first rotor arm module400 a and the hub module 100 are locked together.

In addition to using the locking assembly 420 to lock the first rotorarm module 400 a to the hub module 100, the operator can use the lockingassembly 420 to facilitate mating the male blind mate connector 431 withthe female blind mate connector 231 a. If the male blind mate connector431 and the female blind mate connector 231 a are only partially mated(or not mated at all) and the latch plate engager 423 a of the claw 423is engaged to the claw engager 238 of the latch plate 237, rotating thehandle 422 a of the lever 422 around the first fastener 424 toward thelock/release device 427 to lock the handle 422 a will pull the firstrotor arm module 400 a and the hub module 100 toward one another andcause the male blind mate connector 431 to mate with the female blindmate connector 231 a.

As shown in FIGS. 5D to 5F, the operator reverses this process to unlockthe first rotor arm module 400 a from the hub module 100. The operatorpushes the lock/release device 427 inward with enough force to overcomethe spring-biasing force and to compress the compression spring 429,which causes the lock/release device 427 to rotate to the releaserotational position. This frees the handle 422 a to rotate. Once thehandle 422 a rotates past the locking shelf 427 a, the operator rotatesthe handle 422 a of the lever 422 around the first fastener 424 towardthe latch plate 237 and disengages the latch plate engager 423 a of theclaw 423 from the claw engager 238 of the latch plate 237.

At this point, the operator can either physically pull the first rotorarm module 400 a and the hub module 100 apart to separate the male andfemale blind mate connectors 431 and 231 a or use the locking assembly420 to aid in detachment. When using the locking assembly 420 to aid indetachment, as shown in FIG. 5E, after disengaging the latch plateengager 423 a from the claw engager 238, the operator continues rotatingthe handle 422 a toward the latch plate 237 until the latch plateengager 423 a contacts the backstop 239 of the latch plate 237.Afterward, continued rotation of the handle 422 a toward the latch plate237 causes the latch plate engager 423 a to impose a pushing forceagainst the backstop 239, which forces the first rotor arm module 400 aand the hub module 100 apart, as shown in FIG. 5F.

Turning to the upper and lower rotor motor assemblies 460 a and 460 band the rotor assembly 470 a, the upper and lower rotor motors 465 a and465 b of the upper and lower motor assemblies independently driverespective upper and lower rotors 475 a and 475 b via separate gearreduction trains.

As best shown in FIGS. 5G and 5H, the upper rotor motor assembly 460 aincludes: (1) an upper rotor motor mount 461 a, (2) an upper bearingspider 462 a, (3) an upper pinion 463 a, (4) upper bearings 464 a, (5)the upper rotor motor 465 a, (6) an upper bearing 466 a, (7) an upperbearing cup 467 a, (8) an upper two-piece cooling fan collar 490 a, and(9) an upper rotor motor cooling fan 495 a.

The upper rotor motor 465 a is attached to the upper rotor motor mount461 a. The bearing spider 462 a is attached to the upper rotor motormount 461 a. The upper bearings 464 a are disposed on the motor shaft(not labeled) of the upper rotor motor 465 a. The upper drive pinion 463a is disposed on the upper bearings 464 a and on the motor shaft of theupper rotor motor 465 a such that the upper drive gear 463 a rotateswith the motor shaft. The upper bearing 466 a within the upper bearingcup 467 a is disposed on the motor shaft of the upper rotor motor 465 a.The upper bearing cup 467 a is attached to the upper bearing spider 462a. The upper rotor motor cooling fan 495 a is press-fit around thebottom of the upper rotor motor 465 a and held in place via the uppertwo-piece cooling fan collar 490 a.

The lower rotor motor assembly 460 b includes: (1) a lower rotor motormount 461 b, (2) a lower bearing spider 462 b, (3) a lower pinion 463 b,(4) lower bearings 464 b, (5) the lower rotor motor 465 b, (6) a lowerbearing 466 b, (7) a lower bearing cup 467 b, (8) a lower two-piececooling fan collar 490 b, and (9) a lower rotor motor cooling fan 495 b.

The lower rotor motor 465 b is attached to the lower rotor motor mount461 b. The lower bearing spider 462 b is attached to the lower rotormount 461 b. The lower bearings 464 b are disposed on the motor shaft(not labeled) of the lower rotor motor 465 b. The lower pinion 463 b isdisposed on the lower bearings 464 b and on the motor shaft of the lowerrotor motor 465 b such that the lower pinion 463 b rotates with themotor shaft. The lower bearing 466 b within the lower bearing cup 467 bis disposed on the motor shaft of the lower rotor motor 465 b. The lowerbearing cup 467 b is attached to the lower bearing spider 462 b. Thelower rotor motor cooling fan 495 b is press-fit around the bottom ofthe lower rotor motor 465 a and held in place via the lower two-piececooling fan collar 490 b.

The upper cooling fan collar 490 a and the upper rotor motor cooling fan495 a are shown in detail in FIG. 5I. The lower cooling fan collar 490 band the lower rotor motor cooling fan 495 b are similar to the uppercooling fan collar 490 a and the upper rotor motor cooling fan 495 b andare not separately shown or described for brevity.

The upper rotor motor cooling fan 495 a includes a generally annularbody that defines a plurality of cooling fan openings 496 a through itsside walls (not labeled). A collar connection lip 497 a extends upwardfrom body and radially outward. A generally annular motor mounting shelf498 a extends radially inward from the bottom of the body. A pluralityof motor seats 499 a extend upward from the motor mounting shelf 498 a.

The upper cooling fan collar 490 a includes two identical collar halves491 a having generally half-annular bodies. An upper rotor motor matingsurface 492 a that extends around the (half) circumference of the collarhalf 491 a is grooved to correspond with and mate with grooves on theexterior of the upper rotor motor 465 a. A lip retaining chamber 493 athat extends around the (half) circumference of the collar half 491 a isshaped to receive and retain the lip 497 a of the upper rotor motorcooling fan 495 a.

The bottom of the upper rotor motor 465 a is disposed within the spacedefined by the inner cylindrical surface of the cooling fan 495 a suchthat the bottom of the upper rotor motor 465 a contacts the motor seats499 a. The cooling fan openings 496 a of the cooling fan 495 a aregenerally aligned with corresponding cooling fan openings of the upperrotor motor 465. The collar halves 491 are fit onto the upper rotormotor 465 a and the cooling fan 495 a such that: (1) the lip retainingchambers 493 a of the collar halves 491 receive the lip 497 a of theupper rotor motor cooling fan 495 a; and (2) the upper rotor motormating surfaces 492 a of the collar halves 491 mate with the grooves onthe exterior of the upper rotor motor 465 a. Two fasteners (not labeled)attach the collar halves 491 a to each other to prevent separation.

The cooling fans solve two problems: (1) limited motor power output dueto overheating; and (2) motors falling apart. First, the power output ofthe rotor motors depends to a certain extent on cooling—power outputgenerally decreases the hotter the rotor motors get. The cooling fansenlarge the radius of the cooling fan openings of the rotor motors. Theincreased radius drives cooling air at a greater flow rate, whichimproves cooling and allows motors to be used safely at increased loadswithout fear of failure.

Second, the flux rings of the rotor motors are typically glued onto theend caps of the rotor motors. This attachment is not secure due to thetemperatures the rotor motors reach and the vibrations that occur duringflight. The cooling fan collars double as redundant load paths for themotor flux rings since they mechanically engage the grooves on theexterior of the upper rotor motor, which eliminates the chance of theflux ring working its way off of the end cap.

As best shown in FIG. 5J, the rotor assembly 470 includes a spindle 470a and the following components rotatably mounted to the spindle 470 a:(1) an upper retaining ring 471 a, (2) a lower retaining ring 471 b, (3)upper bearings 472 a and 477 a, (4) lower bearings 472 b and 477 b, (5)upper bearing cups 473 a and 478 a, (6) lower bearing cups 473 b and 478b, (7) an upper torque tube 474 a, (8) a lower torque tube 474 b, (9) anupper rotor 475 a, (10) a lower rotor 475 b, (11) an upper driven gear476 a, (12) a lower driven gear 476 b, (13) an upper spacer 479 a, and(14) a lower spacer 479 b.

Turning to the upper portion of the rotor assembly 470, the bearing 472a is disposed within the bearing cup 473 a, which is fixedly attached tothe top of the rotor 475 a. The torque tube 474 a is fixedly attached atone end to the underside of the rotor 475 a and at the other end to topof the driven gear 476 a. The bearing 477 a is disposed within thebearing cup 478 a, which is fixedly attached to the underside of thedriven gear 476 a. The spacer 479 a is disposed between the bearing 477a and the upper rotor motor mount 461 a. The upper retaining ring 471 ais seated in a groove defined around the spindle 470 a and preventsthese components from sliding off of the spindle 470 a.

Turning to the lower portion of the rotor assembly 470, the bearing 472b is disposed within the bearing cup 473 b, which is fixedly attached tothe bottom of the rotor 475 b. The torque tube 474 b is fixedly attachedat one end to the top of the rotor 475 b and at the other end tounderside of the driven gear 476 b. The bearing 477 b is disposed withinthe bearing cup 478 b, which is fixedly attached to the top of thedriven gear 476 b. The spacer 479 b is disposed between the bearing 477b and the lower rotor motor mount 461 b. The lower retaining ring 471 bis seated in a groove defined around the spindle 470 a and preventsthese components from sliding off of the spindle 470 a.

The spindle 470 a extends through two vertically aligned spindlereceiving openings (not labeled) defined through the rotor arm 410 a.This prevents the spindle 470 a from substantially translating relativeto the rotor arm 410 a. And since all of the components of the upper andlower motor assemblies 460 a and 460 b and the rotor assembly 470 areattached to the spindle 470 a (directly or indirectly), the fact thatthe spindle 470 a extends through the spindle receiving openings definedthrough the rotor arm 410 a prevents any of the components of the upperand lower motor assemblies 460 a and 460 b and the rotor assembly 470from substantially translating relative to the rotor arm 410 a.

To prevent the upper and lower rotor motors 465 a and 465 b (and certaincomponents attached thereto) from rotating relative to the rotor arm 410a, the upper and lower rotor motor mounts 461 a and 461 b are attachedto both an inner bracket 480 a and an outer bracket 480 b. The brackets480 a and 480 b are disposed around the rotor arm 410 a, as best shownin FIGS. 5A, 5B, and 5J.

In operation, the autopilot 272 and the ESC 265 a control the rate anddirection of rotation of the motor shaft of the upper rotor motor 465 a,which drives the upper pinion 463 a, which in turn drives the upperdriven gear 476 a. Since the upper driven gear 476 a is fixedly attachedto the upper rotor 475 a without any further gear reduction, the upperrotor 475 a rotates at the same rate as and in the same rotationaldirection as the upper driven gear 476 a. Similarly, the autopilot 272and the ESC 265 b control the rate and direction of rotation of themotor shaft of the lower rotor motor 465 b, which drives the lowerpinion 463 b, which in turn drives the lower driven gear 476 b. Sincethe lower driven gear 476 b is fixedly attached to the lower rotor 475 bwithout any further gear reduction, the lower rotor 475 b rotates at thesame rate as and in the same rotational direction as the lower drivengear 476 b.

In this embodiment, the upper and lower rotors are generally the samesize and shape. In another embodiment, the lower rotors are larger than(such as about 7% larger than) the upper rotors to compensate for thefact that the lower rotors operate in the upper rotors' downwash.Running larger lower rotors is one way to improve load sharing of upperand lower motors of a multicopter with counter-rotating blades. Anotherway to improve load sharing is to select a lower gear reduction for thelower rotors. Yet another way is to select motors with higher KV(rpm/volt) values. Yet another way is to select lower rotors withcoarser pitch than the upper rotors.

1.3 Front Landing Gear Extension Modules and Landing Gear Modules

FIGS. 6A and 7A show the first front landing gear extension module 500 aand the first front landing gear module 600 a, respectively. The frontlanding gear modules (along with the rear landing gear modules,described below) support the multicopter 10 when assembled but notflying, and facilitate launch and landing of the multicopter 10 withoutdamaging the multicopter 10. The front landing gear extensions are usedto attach the front landing gear to the respective rotor arm modules,and also enable the front landing gear to move relative to the rotor armmodules to prevent rotor rotation in certain instances.

The second front landing gear extension module 500 b and the secondfront landing gear module 600 b are similar to the first front landinggear extension module 500 a and the first front landing gear module 600a and are not separately shown or described for brevity.

The first front landing gear extension module 500 a includes a generallyrectangular hollow support 510 a, a landing gear module securing device520 attached at one end of the support 510 a, and a front landing gearlocking device 530 (which is a cam lever lock in this embodiment but canbe any suitable locking device) attached to the landing gear modulesecuring device 520.

The first front landing gear module 600 a includes a generallycylindrical leg 610, a generally semicircular foot 620 attached to abottom end of the leg 610, and a collar 630 attached near the top end ofthe leg 610 via a fastener 632 (such as a set screw).

The front landing gear locking device 530 enables an operator to attachthe first front landing gear module 600 a to the first front landinggear extension module 500 a. To do so, the operator unlocks the frontlanding gear locking device 530, inserts the first front landing gearmodule 600 a into the landing gear module securing device 520 until thecollar 630 is disposed within the landing gear module securing device520, and re-locks the front landing gear locking device 530. Theoperator reverses this process to detach the first front landing gearmodule 600 a from the first front landing gear extension module 500 a.

The operator attaches the first front landing gear extension module 500a to the first rotor arm module 400 a by inserting the end of thesupport 510 a opposite the end to which the landing gear module securingdevice 520 is attached into the front landing gear extension modulereceiving socket of the first rotor arm module 400 a. The operator thenlocks the first front landing gear extension module 500 a into place,such as using suitable fasteners.

Although not shown, the operator can move the front landing gear modulefurther radially inward or further radially outward by sliding thesupport of the front landing gear extension module further into orfurther out of the rotor arm of the corresponding rotor arm module. Thisenables the operator to move the front landing gear module from a firstposition in which the front landing gear module is clear of the rotorsradially inward to a second position in which the rotors contact thefront landing gear module. When in the second position, the frontlanding gear module prevents the rotors from rotating.

1.4 Rear Landing Gear Extension Modules and Landing Gear Module

FIGS. 6B and 7B show the first rear landing gear extension module 500 cand the first rear landing gear module 600 c, respectively. The rearlanding gear modules (along with the front landing gear modules,described above) support the multicopter 10 when assembled but notflying, and facilitate launch and landing of the multicopter 10 withoutdamaging the multicopter 10. The rear landing gear modules are shapedsuch that they act as vertical stabilizers (or fins) during flight,ensuring that the front of the multicopter 10 (and the nose of thefixed-wing aircraft 20, if attached thereto) points generally into theairflow. The rear landing gear extensions are used to attach the rearlanding gear to the respective rotor arm modules, and also enable therear landing gear to move relative to the rotor arm modules to preventrotor rotation in certain instances.

The second rear landing gear extension module 500 d and the second rearlanding gear module 600 d are similar to the first rear landing gearextension module 500 c and the first rear landing gear module 600 c andare not separately shown or described for brevity.

The first rear landing gear extension module 500 c is an elongatedrectangular hollow support 510 c.

The first rear landing gear module 600 c includes a body having agenerally triangular cross-section that tapers from front to back. Thebody includes two side surfaces 650 a and 650 b and a front surface 650c joining the side surfaces 650 a and 650 b. The side surfaces 650 a and650 b are substantially longer than the front surface 650 c is wide. Thebody tapers at its bottom into a generally circular foot 670. A rearlanding gear extension module receiving socket is defined by a hollowrectangular support 680 extending through the body.

The operator attaches the first rear landing gear extension module 500 cto the third landing gear module 600 c by inserting one end of thesupport 510 c of the first rear landing gear extension module 500 c intothe rear landing gear extension module receiving socket of the support680. The operator then locks the first rear landing gear extensionmodule 500 c into place, such as using suitable fasteners.

The operator attaches the first rear landing gear extension module 500 cto the third rotor arm module 400 c by inserting the end of the support510 c of the first rear landing gear extension module 500 c opposite theend to which the first rear landing gear module 600 c is attached intothe rear landing gear extension module receiving socket of the thirdrotor arm module 400 c. The operator then locks the first rear landinggear extension module 500 c into place, such as using suitablefasteners.

Once attached, the rear landing gear modules are oriented such that theside surfaces of the rear landing gear modules are substantially alignedwith the saddle side brackets 320 a and 320 b of the saddle 300, as bestshown in FIG. 1B. When the fixed-wing aircraft 20 is attached to themulticopter 10, these side surfaces of the rear landing gear modules aresubstantially parallel to a generally vertical plane containing the rollaxis of the fuselage of the fixed-wing aircraft 20. The relatively longlength of these side surfaces of the rear landing gear modules and theirplacement well aft of the center-of-lift of the multicopter 10 cause therear landing gear modules to act as fins. This weathervane effectensures that the nose of the fixed-wing aircraft 20 is oriented into theairflow when airborne. Good flow alignment is critically important forspin avoidance at the moment the multicopter 10 releases the fixed-wingaircraft 20, when the fixed-wing aircraft 20 may be operating well belowstall speed.

In certain embodiments, one or more of the landing gear modules includesa shock absorber.

1.5 Separately Powered Upper and Lower Rotor Motors

As noted above, four batteries 260 a to 260 d power the multicopter 10,though in other embodiments a different quantity of batteries and/ordifferent type(s) of batteries power the multicopter. In otherembodiments, any suitable power source(s), such as a fuel-based powersource or a solar-based power source, may be used instead of or alongwith batteries.

In this embodiment, a first pair of batteries 260 a and 260 b areconnected in series and a second pair of batteries 260 c and 260 d areconnected in series. Here, the first pair of batteries 260 a and 260 bpower the upper rotor motors and do not power the lower rotor motors,while the second pair of batteries 260 c and 260 d power the lower rotormotors and do not power the upper rotor motors. This configurationensures that, if one pair of batteries fails, the multicopter 10 isoperable in a quadcopter mode with either all four upper rotor motors(if the second pair of batteries 260 c and 260 d fails) or all fourlower rotor motors (if the first pair of batteries 260 a and 260 bfails).

The multicopter 10 also includes a gang circuit that connects the twopairs of batteries in parallel to enable a single charger connected toone of the pairs of batteries to also charge the other pair ofbatteries. The gang circuit is overload protected and includes anautomatically resetting circuit breaker. The gang circuit is beneficialbecause it reduces charging time, allowing an operator to recharge bothbatteries in parallel when only one charger is available.

1.6 Multicopter Operating Modes

The multicopter 10 is operable in one of two throttle modes: NORMALthrottle mode and TENSION throttle mode. The multicopter 10 is operablein three different flight modes: ALTHOLD flight mode, LOITER flightmode, and RTL flight mode. The multicopter 10 is operable in ahalf-power mode to, in certain situations, improve response and savepower. The basic functionality of each operating mode is describedbelow. The operator can toggle between these operating modes usingsuitable switches, a touch screen, or any other suitable device on theR/C controller.

On a typical R/C controller including left and right joysticks, the leftjoystick is typically used for throttle, while the right joystick istypically used for left/right and for/aft station-keeping of themulticopter.

1.6.1 SIMPLE Control Mode

SIMPLE control mode simplifies horizontal control by tying the R/Ccontroller's right stick commands to geo-referenced coordinates. Invarious embodiments, the multicopter 10 always operates in SIMPLEcontrol mode, regardless of which of the three flight modes themulticopter 10 employs. Under SIMPLE control mode, forward right stickdeflection drives the multicopter 10 in the direction in which themulticopter 10 was pointed at the instant it was armed, regardless ofits yaw orientation during flight. Put differently, if the multicopter10 was pointed North when armed but, while hovering for instance, themulticopter 10 rotated about its yaw axis such that its nose is pointedEast, forward right stick deflection still drives the multicopter 10North. While the operator may use the left stick to rotate themulticopter 10 about the yaw axis, this (rudder) input is rarely neededfor launch or retrieval of the fixed-wing aircraft 20. The rear landinggear modules ensure the multicopter 10 is pointed into the relative wind(like a weathervane), so the operator need not worry about aligning thefuselage with airflow.

1.6.2 TENSION Throttle Mode

When the multicopter 10 operates in TENSION throttle mode, the humanoperator has direct control over the throttle. In various embodiments,the multicopter 10 can only be operated in TENSION throttle mode when itis operated in either ALTHOLD or LOITER flight modes. That is, themulticopter 10 cannot be operated in TENSION throttle mode when operatedin RTL flight mode. TENSION throttle mode converts throttle stick inputsto direct throttle commands, which is primarily useful for tensioningthe flexible capture tether 5000 during retrieval. An astute operatorwill climb at a controlled rate by feathering the throttle in TENSIONthrottle mode, he will slow high ascent as the tether pulls tight(described below), and then he maintains light tether tension, keepingthe line straight as the fixed-wing aircraft approaches. The straightline allows human observers to confirm that the line will be swept bythe fixed-wing leading edge and the capture is on target. At impact, theoperator increases throttle to arrest the fixed-wing aircraft'shorizontal motion and minimize altitude loss. Then he feathers thethrottle back to lower the aircraft to the ground.

1.6.3 NORMAL Throttle Mode

In NORMAL throttle mode, the autopilot interprets joystick commands asdesired rate commands and applies whatever throttle is needed to achievethat climb or descent rate. When tethered to the ground the altitudecontroller very abruptly increases throttle to maximum (when its desiredaltitude is above current altitude) or it plummets to minimum throttle(when desired altitude is below current altitude) without regard forjoystick position. This behavior makes it difficult or impossible forthe human operator to regulate tether tension directly. Direct throttlecontrol, offered by TENSION throttle mode, disables the altitudecontroller. In this mode, altitude is controlled strictly by tetherlength. In Tension Mode, the human operator controls tether tensiondirectly, with throttle inputs, and the autopilot responds withlift-producing motor commands that are roughly proportional to commandedthrottle position. By this technique, the retrieval process enjoysimproved finesse and precise control without overworking the multicoptermotors and batteries.

1.6.4 ALTHOLD Flight Mode

ALTHOLD flight mode converts throttle commands (left stick, verticalaxis) to vertical rate commands. When operating in the ALTHOLD flightmode, the multicopter 10 will attempt to maintain current altitude whenthe left stick is in the middle position. The multicopter 10 willattempt to climb at up to 5 meters per second (or any other suitablerate) when the left stick is pushed up to max. The multicopter 10 willdescend at up to 5 meters per second (or any other suitable rate) whenthe left stick is pulled to min. ALTHOLD flight mode converts rightstick commands to lean angle, with maximum right stick deflectioncorresponding to 30 degrees (or any other suitable angle). Whenoperating in ALTHOLD flight mode, the multicopter 10 will maintain zerolean when the right stick is in the middle position and will be blowndownwind. If the fixed-wing aircraft 20 is mated to the multicopter 10and producing thrust, this thrust will drive the multicopter 10 forwardunopposed by lean angle. ALTHOLD flight mode does not depend on GPS forcontrol, and works equally well indoors and in all locations where GPSreception is spotty or denied. ALTHOLD flight mode uses a compass fornavigation, which means “SIMPLE MODE” works equally well without the useof GPS. Consequently, the operator simply pushes the right joystickgently into the wind for station keeping, fully into the wind to executea “dash” maneuver (for launch/release), and he will relax the rightstick to allow the aircraft to drift downwind to return home after adash. Finally, the operator will deflect the right stick opposite theaircraft's ground track to minimize ground speed just before touch-down.

1.6.5 LOITER Flight Mode

LOITER flight mode behaves like ALTHOLD flight mode in the verticaldirection (i.e., converts throttle commands to vertical rate commands).Similarly, LOITER flight mode converts right stick inputs to horizontalrate commands. When operating in LOITER flight mode, the multicopter 10attempts to maintain its current horizontal position over the Earth whenthe right stick is in the middle position. Maximum right stickdeflection drives the multicopter 10 in the corresponding direction atup to 20 meters per second ground speed (or any suitable rate) or themaximum achievable speed against true wind, whichever is less. LOITERflight mode depends on GPS to close feedback loops around latitude andlongitude positions. The autopilot 272 will automatically switch itselffrom LOITER flight mode to ALTHOLD flight mode when GPS reception isunacceptable, and will not allow a human operator to arm in LOITERflight mode when GPS reception is unacceptable.

1.6.6 RTL Flight Mode

Return to Launch (RTL) flight mode autonomously returns the multicopter10 to its home position—i.e., the place on Earth where it was lastarmed. When operating in RTL mode, left stick inputs are ignored exceptwhen executing a SHUT DOWN command, and right stick inputs are used onlyduring the final (vertical) descent phase. The operator uses the rightstick to “nudge” the multicopter 10 a designated distance away from thestorage and launch system 2000 to avoid interference at touchdown.Multicopter response to these nudge maneuvers will be similar to rightstick inputs in LOITER flight mode, and the operator should execute thembefore the aircraft descends below 5 meters (or any other suitabledistance) above ground level. To avoid human operator-inducedoscillations and to minimize ground speed, the human operator's fingersshould be kept off the control sticks during final descent and touchdownin RTL mode.

1.6.7 Half-Power Mode

When operating in half-power mode, the multicopter 10 shuts down half ofits rotors—either the lower rotors or the upper rotors—and operatesusing only the remaining half of the rotors. Half-power mode istypically used after the fixed-wing aircraft 20 detaches from themulticopter 10 and the multicopter 10 is returning to its home position.Using all eight rotors to fly just the multicopter 10, which isrelatively light when not carrying the fixed-wing aircraft 20, providestoo much power and induces sluggish response to operator commands. Thisis not ideal, especially when launching the multicopter 10 from an areafull of obstructions that the multicopter 10 must deftly avoid on itsway back to its home position. Operating in half-power mode in theseinstances provides a more appropriate amount of power and enables moreprecise responses to operator commands.

2. Storage and Launch System

The storage and launch system 2000 is shown in FIGS. 8A, 8B, 8C, 8D, 8E,8F, 8G, 8H, and 8I. The storage and launch system 2000 is usable tocompactly store the modular multicopter 10 in a single container afterdisassembly into the 13 modules and to facilitate launch of thefixed-wing aircraft 20 into wing-borne flight by acting as a launchmount for the fixed-wing aircraft 20.

To facilitate storage of the multicopter 10 in a single container(including a container top 2000 a and a container bottom 2000 b), thestorage and launch system 2000 includes: (1) a launch-assist assembly2100 to which the front landing gear modules 600 a and 600 b areattachable; (2) a rotor arm module and rear landing gear module storagedevice 2200 to which the rotor arm modules 400 a to 400 d and the rearlanding gear modules 600 c and 600 d are attachable; and (3) a hubmodule storage tray 2300 to which the hub module 100 is attachable.

To facilitate launch of the fixed-wing aircraft 20, the launch-assistassembly 2100 is movable from a storage position into a launch positionand includes certain elements on which the fixed-wing aircraft can bemounted and other elements that retain the fixed-wing aircraft 20 in alaunch orientation before launch. Example embodiments of each of theseelements are described below, followed by a description of an examplemethod of storing the multicopter 10 using these example embodiments ofthe elements.

2.1 Launch-Assist Assembly

The launch-assist assembly 2100 is attached to the container bottom 2000b and is one element of the storage and launch system 2000 thatfacilitates launch of the fixed-wing aircraft 20. The launch-assistassembly 2100 is movable from a position in which is lies substantiallyflat along the floor of the container bottom 2000 a to enable storage ofthe multicopter 10 to a launch position in which it is generallyspaced-apart from and upwardly angled relative to the floor of thecontainer bottom 2000 a to facilitate launch of the fixed-wing aircraft20.

As best shown in FIG. 8C, the launch-assist assembly 2100 includes: (1)first and second base brackets 2102 a and 2102 b; (2) first and secondfront legs 2104 a and 2104 b; (3) first and second rear legs 2106 a and2106 b; (4) a tray 2108; (5) first and second front landing gear moduleretainers 2110 a and 2110 b; (6) a storage device lock engager 2112; (7)front and rear stabilizing brackets 2114 a and 2114 b; (8) first andsecond lockable gas springs 2116 a and 2116 b; and (9) anaircraft-engaging bracket 2120.

The first and second base brackets 2102 a and 2102 b are attached to thefloor of the container bottom 2000 a near one end. The first front leg2104 a is pivotably attached at one end to the front end of the firstbase bracket 2102 a and pivotably attached at the other end to the tray2108. Similarly, the second front leg 2104 b is pivotably attached atone end to the front end of the second base bracket 2102 b and pivotablyattached at the other end to the tray 2108. The first rear leg 2106 a ispivotably attached at one end to the rear end of the first base bracket2102 a and pivotably attached at the other end to the tray 2108.Similarly, the second rear leg 2106 b is pivotably attached at one endto the rear end of the second base bracket 2102 b and pivotably attachedat the other end to the tray 2108. The front stabilizing bracket 2114 ais attached to and extends between the first and second front legs 2104a and 2104 b, and the rear stabilizing bracket 2114 b is attached to andextends between the first and second rear legs 2106 a and 2106 b. Thefirst lockable gas spring 2116 a is pivotably attached at one end to thefirst base bracket 2102 a between the first front leg 2104 a and thefirst rear leg 2106 a and pivotably attached at the other end to thefirst front leg 2104 a between the first base bracket 2102 a and thetray 2108. Similarly, the second lockable gas spring 2116 b is pivotablyattached at one end to the second base bracket 2102 b between the secondfront leg 2104 b and the second rear leg 2106 b and pivotably attachedat the other end to the second front leg 2104 b between the second basebracket 2102 b and the tray 2108. The storage device lock engager 2112,the first and second front landing gear module retainers 2110 a and 2110b, and the aircraft engaging bracket 2120 are attached to the tray 2108.

The aircraft engaging bracket 2120 includes two spaced-apart generallyparallel sides 2121 and 2123 having wing engaging surfaces 2121 a and2123 a, respectively, and a back 2122 transverse (such as generallyperpendicular) to, extending between, and connecting the sides 2121 and2123. A fuselage-retaining assembly 2130 is rotatably mounted to theback plate 2122.

The above-described pivotable attachments enable the launch assistassembly 2100 to move from: (1) a storage position in which the firstand second front legs 2104 a and 2104 b, the first and second back legs2106 a and 2106 b, and the tray 2108 lay substantially flat along thefloor of the container bottom 2000 a (as best shown in FIGS. 8A and 8B);to (2) a launch position in which the first and second front legs 2104 aand 2104 b and the first and second back legs 2106 a and 2106 b extendupward from the floor of the container bottom 2000 a such that the tray2108 is spaced-apart from and upwardly angled relative to the floor ofthe container bottom 2000 a (as best shown in FIGS. 8C and 8D) (andvice-versa). The operator can lock the launch assist assembly 2100 inthe launch position by locking the first and second lockable gas springs2116 a and 2116 b.

When in the launch position, the launch assist assembly 2100 facilitateslaunch of the fixed-wing aircraft 20 by orienting the fixed-wingaircraft 20 in a desired launch orientation and retaining the fixed-wingaircraft 20 in that orientation until the operator desires to launch thefixed-wing aircraft 20. As best shown in FIG. 8D, in preparation forlaunch, the operator inserts the fuselage of the fixed-wing aircraft 20into the fuselage-retaining assembly 2130 of the aircraft engagingbracket 2120 and lays the wings of the fixed-wing aircraft 20 atop thefirst and second wing engaging surfaces 2123 a and 2123 b of theaircraft engaging bracket 2120.

The fuselage-retaining assembly 2130 is sized to receive the fuselage ofthe fixed-wing aircraft 20. The fuselage-retaining assembly 2130 isconfigured such that, after it receives the fuselage, thefuselage-retaining assembly 2130 does not release the fuselage until:(1) the operator disengages a safety mechanism; and (2) a force biasingthe fuselage-retaining assembly 2130 against releasing the fuselage isovercome. This prevents undesired launch of the fixed-wing aircraft 20.

As best shown in FIGS. 8E, 8F, and 8G, the fuselage-retaining assembly2130 includes: (1) first and second pincers 2132 and 2134; (2) first andsecond rollers 2136 and 2138 and corresponding nuts 2136 a and 2138 a;(3) a grooved clevis pin 2140 and corresponding retaining ring 2140 a,spacer 2140 b, and washer 2140 c; (4) first and second spring mountingspacers 2142 and 2144 and their corresponding fasteners 2142 a and 2144a and nuts 2142 b and 2144 b; (5) a compression spring 2146; and (6) asafety mechanism 2150.

The safety mechanism 2150 includes: (1) front and rear plates 2151 and2152; (2) fasteners 2154 a and 2154 e; (3) clevis pins 2154 b, 2154 c,and 2154 d; (4) spacers 2156 a and 2156 e; (5) a rod end 2156 b; (6) acompression spring 2158; and (7) a handle 2160.

The first and second pincers 2132 and 2134 are interchangeable, and havegenerally curved bodies that define rod end engagers 2132 a and 2134 a,respectively, along their outer edges and terminate at their lower endsin safety mechanism engagers 2132 b and 2134 b. The roller 2136 isattached via the nut 2136 a to the upper end of the first pincer 2132,and the roller 2138 is attached via the nut 2138 a to the upper end ofthe second pincer 2134. The rollers are rotatable with respect to theirrespective pincers. The first and second pincers 2132 and 2134 arepivotably connected to one another via the grooved clevis pin 2140, thespacer 2140 b, the washer 2140 c, and the retaining ring 2140 a.Although not shown, the fuselage-retaining assembly 2130 is attached tothe aircraft engaging bracket 2120 via this grooved clevis pin 2140.

In this embodiment, the first pincer is mounted on the grooved clevispin in front of the second pincer (with respect to the view shown inFIG. 8E), though in other embodiments the second pincer may be mountedin front of the first pincer without changing how the fuselage-retainingassembly operates.

As best shown in FIG. 8G, the spring mounting spacer 2142 is mounted toa backwardly extending portion of the first pincer 2132 via the fastener2142 a and the nut 2142 b. Similarly, the spring mounting spacer 2144 ismounted to a backwardly extending portion of the second pincer 2134 viathe fastener 2144 a and the nut 2144 b. The compression spring 2146 ismounted on and extends between the spring mounting spacers 2142 and2144.

The first and second pincers 2132 and 2134 are movable relative to oneanother from: (1) a fuselage-retaining orientation in which their upperends are separated a first distance that is smaller than the diameter ofthe fuselage of the fixed-wing aircraft 20 (shown in FIGS. 8E and 8F);to (2) a fuselage-release orientation in which their upper ends areseparated a second distance that is larger than the diameter of thefuselage of the fixed-wing aircraft 20 (not shown) (and vice-versa).Thus, when the first and second pincers 2132 and 2134 are in thefuselage-retaining orientation, the fuselage of the fixed-wing aircraftcannot escape the first and second pincers 2132 and 2134 (absent furtherseparation of the pincers), while the fuselage can escape when the firstand second pincers 2132 and 2134 are in the fuselage-releaseorientation.

The compression spring 2146 opposes separation of the first and secondpincers 2132 and 2134 and therefore biases the first and second pincers2132 and 2134 toward the fuselage-retaining orientation. Separating thefirst and second pincers 2132 and 2134 causes the backwardly extendingportions of the first and second pincers 2132 and 2134 to compress thecompression spring 2146, which causes the compression spring 2146 toexert forces on the backwardly extending portions of the first andsecond pincers 2132 and 2134 opposing that separation. Thus, to releasethe fuselage, this biasing force must be overcome.

Turning to the safety mechanism 2150, as best shown in FIG. 8E, thefront plate 2151, the rear plate 2152, and the handle 2160 are attachedto one another via: (1) the fastener 2154 a extending through an opening2152 a in the rear plate 2152, through the spacer 2156 a, through anopening 2151 a in the front plate 2151, and into the handle 2160; (2)the clevis pin 2154 b extending through an opening 2152 a in the rearplate 2152, through an opening in the rod end 2156 b, and through anopening 2151 b in the front plate 2151; (3) the clevis pin 2154 dextending through an opening 2152 d in the second plate and an opening2151 d in the front plate 2151; and (4) the fastener 2154 e extendingthrough an opening 2152 e in the rear plate 2152, through the spacer2156 e, and through an opening 2151 e in the front plate 2151.

As best shown in FIGS. 8E and 8F, the safety mechanism 2150 is pivotablyconnected to the second pincer 2134 via the clevis pin 2154 c extendingthrough an opening 2152 c in the rear plate 2152, an opening 2134 c inthe second pincer 2134, and an opening 2151 c in the front plate 2151.One end of the safety compression spring 2158 is disposed around the rodend 2156 b and the other end of the safety compression spring 2158 isdisposed around the rod end engager 2134 a of the second pincer 2134.

The safety mechanism 2150 is rotatable about the clevis pin 2134 c froman engaged rotational position in which the safety mechanism 2150prevents separation of the first and second pincers 2132 and 2134 fromthe fuselage-retaining orientation to the fuselage-release orientation(shown in FIGS. 8F and 8G) to a disengaged rotational position (notshown) in which the first and second pincers 2132 and 2134 are free toseparate from the fuselage-retaining orientation to the fuselage-releaseorientation. The safety compression spring 2158 biases the safetymechanism 2150 into the engaged rotational position.

When in the engaged rotational position, the safety mechanism 2150prevents separation of the first and second pincers 2132 and 2134 fromthe fuselage-retaining orientation to the fuselage-release orientation.Separating the first and second pincers 2132 and 2134 when the safetymechanism 2150 is in the engaged rotational position results in: (1) thesafety mechanism engager 2132 b of the first pincer 2132 engaging theclevis pin 2154 d (since the clevis pin 2154 d is in the path ofrotation of the safety mechanism engager 2132 b of the first pincer2132); and (2) the rod end engager 2134 a of the second pincer 2134engaging the rod end 2136 b. This prevents the first and second pincers2132 and 2134 from rotation relative to one another and thereforeprevents further separation of the first and second pincers 2132 and2134 to the fuselage-release orientation.

To enable the first and second pincers 2132 and 2134 to separate fromthe fuselage-retaining orientation to the fuselage-release orientation,the operator disengages the safety mechanism by rotating the safetymechanism 2150 from the engaged rotational position to the disengagedrotational position. To do so, the operator pulls the handle 2160 upwardwith enough force to overcome the spring-biasing force of thecompression spring 2158 and compress the compression spring 2158 untilthe clevis pin 2154 d is no longer in the path of rotation of the safetymechanism engager 2132 b of the first pincer 2132. At this point, thesafety mechanism 2150 is in the disengaged rotational position, and thefirst and second pincers 2132 and 2134 can separate to thefuselage-release orientation.

In certain embodiments, a safety rope, tether, wire, cable, or otherflexible member is attached to the handle (or any other suitablecomponent) of the safety mechanism to facilitate disengaging the safetymechanism. When the flexible safety member is tensioned (such as via anoperator pulling on the flexible safety member), the safety mechanismrotates from the engaged rotational position to the disengagedrotational position, thereby disengaging the safety mechanism. Theflexible safety member may be relatively long, which enables theoperator to stand a safe distance away from the fixed-wing aircraftduring the launch process and still be able to disengage the safetymechanism.

By intentionally commanding full multicopter thrust without releasingthe safety mechanism, an operator may execute a “refuse takeoff” test,which is particularly useful for confirming full-power performance ofthe complete electromechanical system without fear of flight-relatedmishap in the event that one or more components of the system shouldfail during the test.

2.2 Rotor Arm Module and Rear Landing Gear Module Storage Device

The rotor arm module and rear landing gear module storage device 2200 isshown in FIGS. 8H and 8I. The rotor arm module and rear landing gearmodule storage device 2200 is the element of the storage and launchsystem 2000 to which the rotor arm modules 400 a to 400 d and the rearlanding gear modules 600 c and 600 d can be mounted and compactlystored. The rotor arm module and rear landing gear module storage device2200 includes: (1) a base 2205; (2) a handle 2210; (3) an upper rotorarm module constraining plate 2230; (4) a lower rotor arm moduleconstraining plate 2250; and (5) a lock 2220 (which is a slide bolt inthis embodiment but can be any suitable device).

The base 2205 defines a storage device lock engager receiving cavity2205 a therethrough sized to receive the storage device lock engager2112 of the launch-assist assembly 2100. The lock 2220 is fixedlyattached to the base 2205 near the storage device lock engager receivingcavity such that the lock 2220 can engage the storage device lockengager 2112 when the storage device lock engager 2112 is received inthe storage device lock engager receiving cavity 2205 a to lock therotor arm module and rear landing gear module storage device 2200 to thelaunch assist assembly 2100.

The handle 2210 includes two opposing, spaced-apart sides 2211 and 2213and a top 2212 extending between the sides 2211 and 2213. The sides 2211and 2213 are attached to the base 2205. The side 2211 includes twosurfaces 2211 a and 2211 b each defining a rear landing gear modulereceiving cavity sized and shaped to receive a portion of one of therear landing gear modules 600 c and 600 d.

The upper rotor arm module constraining plate 2230 is attached to thehandle 2210. The upper rotor arm module constraining plate 2230 includesa plurality of surfaces 2230 a, 2230 b, 2230 c, and 2230 d each defininga rotor motor receiving cavity sized and shaped to receive a rotor motorof one of the rotor arm modules.

The upper rotor arm module constraining plate 2230 also includes aplurality of rotor arm module retainers 2241, 2242, 2243, and 2244disposed within an enclosing bracket 2240. The rotor arm module retainer2241 includes a locking tab 2241 a extending below the upper rotor armmodule constraining plate 2230 and is pivotably connected to the upperrotor arm module constraining plate 2230 via a pin 2241 b. The rotor armmodule retainer 2242 includes a locking tab 2242 a extending below theupper rotor arm module constraining plate 2230 and is pivotablyconnected to the upper rotor arm module constraining plate 2230 via apin 2242 b. The rotor arm module retainer 2243 includes a locking tab2243 a extending below the upper rotor arm module constraining plate2230 and is pivotably connected to the upper rotor arm moduleconstraining plate 2230 via a pin 2243 b. The rotor arm module retainer2244 includes a locking tab 2244 a extending below the upper rotor armmodule constraining plate 2230 and is pivotably connected to the upperrotor arm module constraining plate 2230 via a pin 2244 b.

The rotor arm module retainers are pivotable from a lock rotationalposition (shown in FIG. 8I) to a release rotational position (notshown). Suitable biasing elements (such as compression spring, notshown) bias the rotor arm module retainers to the lock rotationalposition.

The lower rotor arm module constraining plate 2250 is attached to thehandle 2210 below the upper rotor arm module constraining plate 2230.The lower rotor arm module constraining plate 2250 includes a pluralityof surfaces 2250 a, 2250 b, 2250 c, and 2250 d each defining a rotormotor receiving cavity sized and shaped to receive a rotor motor of oneof the rotor arm modules.

2.3 Hub Module Storage Tray

The hub module storage tray 2300 is shown in FIG. 8J. The hub modulestorage tray 2300 is the element of the storage and launch system 2000to which the hub module 200 is mounted for storage. The hub modulestorage tray 2300 includes a generally rectangular base 2310, a handle2320 fixedly attached to the base 2310, and four female blind mateconnector engagers 2332, 2334, 2336, and 2338 fixedly attached to thebase 2310. The female blind mate connector engagers are sized and shapedto engage the top surfaces of the female blind mate connectors 231 ofthe hub module 100.

2.4 Storing the Multicopter in the Multicopter Storage Container

To store the multicopter 10 in the container of the storage and launchsystem 2000, the operator first disassembles the multicopter 10 into the13 modules or subassemblies, as described above. The operator moves thelaunch-assist assembly 2100 into its launch position.

The operator positions the rotor arm module and rear landing gear modulestorage device 2200 atop the launch-assist assembly 2100 such that thestorage device lock engager 2112 of the launch-assist assembly 2100 isreceived in the storage device lock engager receiving cavity 2205 a. Theoperator engages the storage device lock engager 2112 with the lock 2220to lock the rotor arm module and rear landing gear module storage device2200 to the launch assist assembly 2100.

The operator slides the rotor arm module 400 a into the space betweenthe upper and lower rotor arm module constraining plates 2230 and 2250of the rotor arm module and rear landing gear module storage device 2200until: (1) the lower rotor motor is disposed within the rotor motorreceiving cavities defined by the surfaces 2230 b and 2250 b; and (2)the rotor arm module retainer 2243 locks the rotor arm module 400 a intoplace.

The operator slides the rotor arm module 400 b into the space betweenthe upper and lower rotor arm module constraining plates 2230 and 2250of the rotor arm module and rear landing gear module storage device 2200until: (1) the lower rotor motor is disposed within the rotor motorreceiving cavities defined by the surfaces 2230 d and 2250 d; and (2)the rotor arm module retainer 2242 locks the rotor arm module 400 b intoplace.

The operator slides the rotor arm module 400 c into the space betweenthe upper and lower rotor arm module constraining plates 2230 and 2250of the rotor arm module and rear landing gear module storage device 2200until: (1) the upper rotor motor is disposed within the rotor motorreceiving cavities defined by the surfaces 2230 c and 2250 c; and (2)the rotor arm module retainer 2241 locks the rotor arm module 400 c intoplace.

The operator slides the rotor arm module 400 d into the space betweenthe upper and lower rotor arm module constraining plates 2230 and 2250of the rotor arm module and rear landing gear module storage device 2200until: (1) the upper rotor motor is disposed within the rotor motorreceiving cavities defined by the surfaces 2230 a and 2250 a; and (2)the rotor arm module retainer 2244 locks the rotor arm module 400 d intoplace.

The operator inserts the front landing gear modules 600 a and 600 b intothe first and second front landing gear module retainers 2110 a and 2110b on the tray 2108 of the launch-assist assembly 2100.

The operator inserts the rear landing gear module 600 c into the rearlanding gear module receiving cavity defined by the surface 2211 b andthe rear landing gear module 600 d into the rear landing gear modulereceiving cavity defined by the surface 2211 a.

The operator places the landing gear extensions 500 a to 500 d in thecontainer bottom 2000 a behind the handle 2320 of the hub module storagetray 2300. The operator attaches the container top 2000 b to thecontainer bottom 2000 a to complete storage.

The operator inverts the hub module 100 and engages the female blindmate connector engagers 2332, 2334, 2336, and 2338 of the hub modulestorage tray 2300 with the female blind mate connectors 231 of the hubmodule 100.

The operator moves the launch-assist assembly 2100 to the storageposition.

In certain embodiments, the container top or the container bottomincludes one or more handles (such as an extendable handle) or one ormore wheels to facilitate moving the container. In certain embodiments,the container top or the container bottom includes one or more locksconfigured to lock the container top to the container bottom.

3. Anchor System

The anchor system 3000 is shown in FIGS. 9A to 9D. The anchor system3000 is usable along with the multicopter 10 and the flexible capturemember 5000 to retrieve the fixed-wing aircraft 20 from wing-borneflight. In this example embodiment, the anchor system 3000 is storedseparately from the storage and launch system 2000. That is, the storageand launch system 2000 is stored in one container (along with themulticopter 10) and the anchor system 3000 is stored in anothercontainer. These containers may be identical to or different from oneanother.

As best shown in FIGS. 9A and 9B, the anchor system includes: (1) ananchor system base 3100; (2) a breakaway device 3200 attached to theanchor system base 3100; and (3) a flexible capture member payout andretract device 3300 attached to the anchor system base 3100. Exampleembodiments of each of these elements are described below.

3.1 Anchor System Base

As best shown in FIGS. 9A and 9B, the anchor system base 3100 is theelement of the anchor assembly 3000 that serves as a mount for theremaining elements of the anchor system 3000. The anchor system base3100 includes two spaced-apart generally parallel sides 3102 and 3104and a top 3106 transverse (such as generally perpendicular) to,extending between, and connecting the sides 3102 and 3104.

The side 3102 defines: (1) first, second, and third braking openings3102 a, 3102 b, and 3102 c therethrough; (2) a stator mounting opening3102 d therethrough; and (3) a locking element engager receiving opening3102 e therethrough. The side 3104 defines similar openingstherethrough, some of which are not shown or labeled.

The top 3106 defines: (1) a fairlead mounting opening 3106 atherethrough; (2) a U-joint mounting opening 3106 b therethrough; and(3) a GPS antenna mounting opening 3106 c therethrough.

A GPS antenna and U-joint mount 3816 is attached to the underside of thetop 3106 of the anchor system base 3100 such that it is positionedwithin the cavity formed by the sides 3102 and 3104 and the top 3106. AGPS antenna 3810 is attached to the GPS antenna and U-joint mount 3816such that the GPS antenna 3810 extends through the GPS antenna mountingopening 3106 c of the top 3106. A U-joint 3814 is attached to the GPSantenna and U-joint mount 3816 such that the U-joint 3814 extendsthrough the U-joint mounting opening 3106 b of the top 3106.

A fairlead 3812 is attached to the upper surface of the top 3106 suchthat a flexible capture member receiving opening 3812 a defined throughthe fairlead 3812 is generally aligned with the fairlead mountingopening 3106 a of the top 3106.

Backing plates 3116 a, 3116 b, and 3116 c are attached to the exteriorsurface of the side 3102 such that they generally cover the brakingopenings 3102 a, 3102 b, and 3102 c, respectively. Backing plates 3116d, 3116 e, and 3116 f are attached to the exterior surface of the side3104 such that they generally cover respective braking openings (notshown). The backing plates 3116 a to 3116 f are made of iron in thisembodiment. Magnets 3318 a are attached to the backing plate 3116 a suchthat the magnets 3318 a extend through the braking opening 3102 a,magnets 3318 b are attached to the backing plate 3116 b such that themagnets 3318 b extend through the braking opening 3102 b, and magnets3318 c are attached to the backing plate 3116 c such that the magnets3318 c extend through the braking opening 3102 c. Similar magnets areattached to the backing plates 3316 d, 3316 e, and 3316 f. FIG. 9B showsthe magnets' position relative to the first flange of the flexiblecapture member and payout device (described below).

A rotation prevention device 3120 is also attached to the exteriorsurface of the side 3102 near the locking element engager receivingopening 2102 e of the side 3012. The rotation prevention device 3120includes a mount 3122 (such as a pillow block bearing), a retract spring(not shown), and a pawl 3124 pivotably attached to the mount 3122. Alocking element engager 3126 extends from the free end of the pawl 3124.The rotation prevention device 3120 is attached to the side 3102 suchthat the locking element engager 3126 extends through the lockingelement engager receiving opening 3102 e. The pawl 3124 is rotatableabout its pivotable attachment to the mount 3122 from a locked positionin which the locking element engager 3126 contacts the end cap 3314 andcan engage the locking element 3314 a and an unlocked position in whichthe locking element engager does not contact the end cap 3314 and cannotengage the locking element 3314 a. The rotation-prevention device 3120automatically retracts in the payout direction, and it remains clear asthe flexible capture member payout and retract device (described below)retracts the flexible capture member post-capture. This automaticallyretracting rotation prevention device 3120 enables an operator topreload the flexible capture member payout and retract device duringpreflight and, upon impact during capture, the flexible capture memberpayout and retract device can retract more flexible capture memberlength than it paid out. This feature is particularly useful forminimizing pendula swing of the fixed wing aircraft 20 as it is loweredto the ground post-capture.

3.2 Breakaway Device

As best shown in FIG. 9C, the breakaway device 3200 enables themulticopter 10 to maintain a desired tension in the flexible capturemember 5000 before the fixed-wing aircraft 20 captures the flexiblecapture member 5000 during retrieval. The breakaway device 3200 preventsthe flexible capture member payout and retract device 3300 from payingout or retracting the flexible capture member 5000 until a tension inthe flexible capture member 5000 reaches a certain threshold duringretrieval. The breakaway device 3200 includes: (1) a generallycylindrical hollow shaft 3210; (2) a lower retaining ring 3212; (3) agenerally annular collar 3214; (4) a compression spring 3216; (5) anupper retaining ring 3218; and (6) a breakaway sleeve 3220.

The shaft 3210 defines an upper retaining ring seat 3210 a near itsupper end in which the upper retaining ring 3218 is seated such that theupper retaining ring 3218 cannot slide along the shaft 3210 and aplurality of grooves forming a lower retaining ring seat 3210 b in whichthe lower retaining ring 3212 is seated such that the lower retainingring 3212 cannot slide along the shaft 3210.

The collar 3214 is slidably mounted around the shaft 3210 between theupper retaining ring 3218 and the lower retaining ring 3212. The collarincludes a plurality of breakaway sleeve retainers 3214 a that extendradially outward from the outer surface of the collar 3214.

The compression spring 3216 is slidably mounted around the shaft 3210between the upper retaining ring 3218 and the collar 3214.

The breakaway sleeve 3220 includes a generally cylindrical hollow body3222 and a cap 3224 at its upper end. The lower end of the body 3222defines a plurality of breakaway sleeve retainer receiving slots 3222 atherethrough. The breakaway sleeve retainer receiving slots 3222 a areopen at one end, extend generally upward and circumferentially aroundthe body 3222, and dip slightly downward before terminating. A finger3228 is pivotably attached to the cap 3224 via a suitable fastener 3230(such as a grooved clevis pin and retaining ring). The body 3222 and thecap 3224 define a finger escape slot 3226 therethrough. The finger 3228is rotatable from a rotational position in which the free end 3228 a ofthe finger 3228 is located within the interior of the breakaway sleeve3220 to a rotational position in which the free end 3228 a is outside ofthe interior of the breakaway sleeve 3220 (after passing through thefinger escape slot 3226).

The breakaway sleeve 3220 is removably attachable to the collar 3214 viathe breakaway sleeve retainers 3214 a and the breakaway sleeve retainerreceiving slots 3222 a. To attach the breakaway sleeve 3220 to thecollar 3214, the operator: (1) aligns the openings of the breakawaysleeve retainer receiving slots 3222 a of the breakaway sleeve 3220 withthe breakaway sleeve retainers 3214 a of the collar 3214; (2) pushesdownward on the breakaway sleeve 3220 to slightly compress thecompression spring 3216 until the openings of the breakaway sleeveretainer receiving slots 3222 a receive the breakaway sleeve retainers3214 a; (3) rotates the breakaway sleeve 3220 with respect to the collar3214 such that the breakaway sleeve retainers travel through and to theend of their respective breakaway sleeve retainer receiving slots 3222 a(clockwise with respect to the view shown in FIG. 9C); and (4) releasesthe breakaway sleeve 3220, which enables the compression spring 3216 toextend and lock the breakaway sleeve retainers 3214 a within theirrespective breakaway sleeve retainer receiving slots 3222 a. To detachthe breakaway sleeve 3220 form the collar 3214, the operator reversesthe process.

The breakaway device 3220 is fixedly attached to the U-joint 3814 of theanchor system base 3100.

3.3 Flexible Capture Member Payout and Retract Device

As best shown in FIG. 9B, the flexible capture member payout and retractdevice 3300 absorbs a portion of the kinetic energy of the fixed-wingaircraft 20 after the fixed-wing aircraft 20 captures the flexiblecapture member 5000 by paying out part of the flexible capture member5000 after capture from a spool while simultaneously applying variousbraking forces to the spool to slow the aircraft. As the aircraft slowsand comes to a stop, flexible capture member payout and retract device3300 retracts at least part of the paid-out flexible capture member 5000to generally prevent the now-dangling fixed-wing aircraft 20 fromswinging around below the multicopter 10.

The flexible capture member payout and retract device 3300 includes: (1)a stator 3310; (2) a drum 3312 rotatably mounted to the stator 3310; (3)a first electrically conductive flange 3314 having a locking element3314 a extending therefrom and fixedly attached to one end of the drum3312; and (4) a second electrically conductive flange 3316 fixedlyattached to the opposite end of the drum 3312.

The flexible capture member payout and retract device 3300 is attachedto the anchor system base 3100 via the stator 3310. Specifically, theflexible capture member payout and retract device 3300 is attached tothe anchor system base 3100 such that the stator 3310 extends betweenthe first and second stator mounting openings 3102 d and 3104 d of thefirst and second sides 3102 and 3104 of the anchor system base 3100.

Although not shown, the flexible capture member payout and retractdevice 3300 also includes a suitable biasing element—such as a powerspring—disposed within the interior of the drum 3312. Inside the drum3312, the arbor end of the power spring is anchored to the stator 3310.Upon impact, during retrieval, the power spring is forced to wrap aroundthe stator 3310, transferring wraps from the drum 3312 to the stator3310 inside the flexible capture member payout and retract device 3300.After the kinetic energy of the fixed-wing aircraft 20 has beenabsorbed, the power spring works to retract (i.e., reverse payout) ofthe flexible capture member. This payout reversal helps in two ways: (1)it attenuates the backswing tendency of the captured fixed-wing aircraft20, and (2) it allows the operator to begin a controlled descent of thefixed-wing aircraft 20 to the ground.

3.4 Flexible Capture Member

As best shown in FIG. 10D, a flexible capture member 5000 is attachableto the multicopter 10 and the anchor system 3000 to facilitate retrievalof the fixed-wing aircraft 20 from wing-borne flight. The flexiblecapture member 5000 includes: (1) an elastic portion 5100; (2) a captureportion 5200; and (3) a retractable portion 5300.

The elastic portion 5100 is a bungee or similar element, and isattachable at one end to the cam 350 of the hub module 100 and at theother end to the capture portion 5200. The elastic portion may be riggedsuch that a portion of the strain energy is directed into a dampingelement such as a metal ring or a one-way pulley. By rigging the elasticportion as a compliant damper (as opposed to a spring), more energy isabsorbed during capture, and undesirable ricochet is minimized.

The capture portion 5200 is a rope or similar element (such as Spectrarope) attachable at one end to the elastic portion 5100 and at the otherend to the retractable portion 5300. The capture portion 5200 is theportion of the flexible capture member 5000 that the fixed-wing aircraft20 captures during retrieval. Here, the capture portion 5200 is thickernear its ends (such as within 12 feet of each end) that it is in itscenter. In one embodiment, both ends of the capture portion terminate ina Brummel eye splice in which the buried tails constitute the thickerportion of the capture portion 5200.

The retractable portion 5300 is a rope or similar element attachable atone end to the capture portion 5200, partially wound around the drum3312 of the flexible capture member payout and retract device 3300, andattached to the flexible capture member payout and retract device 3300.The retractable portion may be further improved by inserting an elasticmember inside the core of the rope. The elastic member shortens the ropeas it slackens and is wound onto the drum. During payout, the elasticmember allows the rope to lengthen as it leaves the drum, and a lossypayout device is formed. This detail is especially helpful during adynamic braking event, in which spool inertia and limited power springstroke can impart undesirable acceleration spikes on the aircraft.

3.5 Accessories Container and Other Components

As best shown in FIG. 9D, the anchor system 3000 is attached to thecontainer bottom 4000 b of an anchor system and accessory storagecontainer to enable easy and compact storage of the anchor system 3000and various accessories, such as (but not limited to): (1) a batterycharger 4010 usable to recharge the batteries 260 a to 260 d of themulticopter 10; (2) an engine cooling system 4020 usable duringpre-launch of the fixed-wing aircraft 20 to cool the engine of thefixed-wing aircraft 20; (3) two generators 4030 a and 4030 b; (4) theflexible capture member 5000; (5) an R/C transmitter stand that helpsenforce geo-referenced joystick commands of the R/C controller; (6)extra nozzles for the engine cooling system; (7) a fire extinguisher;(8) shovels; (9) hard hats; (10) a parallel cable usable to enable thegenerators 4030 a and 4030 b to load-share; (11) an extra fuel tank;(12) spare hooks for the fixed-wing aircraft 20; (13) a laptop computer;and (14) weights for ballast.

4. Methods of Operation

As described in detail below: (1) the multicopter 10 and the storage andlaunch system 2000 are usable to facilitate launch of the fixed-wingaircraft 20 into wing-borne flight; and (2) the multicopter 10, theanchor system 3000, and the flexible capture member 5000 are usable tofacilitate retrieval of the fixed-wing aircraft 20 from wing-borneflight.

4.1 Multicopter-Assisted Fixed-Wing Aircraft Launch Method

The multicopter-assisted fixed-wing aircraft launch method begins withthe multicopter 10 disassembled and stored in the storage and launchsystem 2000, as best shown in FIGS. 8A and 8B. The operator unpacks the13 modules and moves the launch-assist assembly 2100 of the storage andlaunch system 2000 to its launch position, as best shown in FIG. 8C.

The operator mounts the fixed-wing aircraft 20 to the launch-assistassembly 2100 by: (1) disengaging the safety mechanism 2150 of thefuselage-retaining assembly 2130, which enables the pincers 2132 and2134 to separate from the fuselage-retaining orientation to thefuselage-release orientation; (2) lowering the fuselage of thefixed-wing aircraft 20 between the pincers 2132 and 2134 (the fact thatthe safety mechanism 2150 is disengaged enables weight of the fixed-wingaircraft to force the pincers 2132 and 2134 to separate to receive thefuselage); (3) positioning the wings of the fixed-wing aircraft 20 onthe wing engaging surfaces 2121 a and 2123 a of the aircraft engagingbracket 2120 of the launch-assist assembly 2100; and (4) engaging thesafety mechanism 2150, which prevents the pincers 2132 and 2134 fromseparating to the fuselage-release position and retains the fuselage ofthe fixed-wing aircraft 20 between the pincers 2132 and 2134. FIG. 8Dshows the fixed-wing aircraft 20 mounted to the launch-assist assembly2100 in this manner.

The operator selects the appropriate cooling nozzle for the enginecooling system 4020 based on the type of fixed-wing aircraft 20 used.The operator attaches that cooling nozzle to the engine cooling system4020 and hangs the engine cooling system 4020 on the back of theaircraft engaging bracket 2120 of the launch-assist assembly 2100 suchthat the engine of the fixed-wing aircraft 20 is in the cooling nozzle'spath.

The operator switches an idle power circuit of the multicopter 10 to aclosed state (from an open state) to power certain components of themulticopter 10—such as the GPS receiver, the controller, and the IMU—toenable various preflight checks (e.g., operating mode status checks,throttle response checks, attitude indicator response checks, headingaccuracy checks, and R/C range checks) to be performed. Switching theidle power circuit to the closed state does not power the rotor motors.The idle power circuit thus (when closed) enables the operator toconduct most preflight checks without having to worry about accidentallyswitching on one or more of the rotor motors.

As shown in FIG. 10A, the operator then attaches the hub module 100 tothe fixed-wing aircraft 20 by: (1) operating the cam servo motor 381(either manually or remotely via the R/C controller) to rotate the cam350 to the attached rotational position (clockwise from this viewpoint);(2) operating the lock servo motor 391 (either manually or remotely viathe R/C controller) to rotate the lock servo motor arm 392 into the camrotation-preventing rotational position (clockwise from this viewpoint)such that the lock servo motor locking extension 392 a on the end of thelock servo arm 392 engages the cam servo motor arm lock device 382 a ofthe cam servo motor arm 382; and (3) seating a rearwardly curved hook 21attached to the fuselage of the fixed-wing aircraft 20 on the cam 350such that hook generally rests on the ridge 351 of the cam 350 and thetip of the hook is disposed in the valley 353 of the cam 350.

At this point the fixed-wing aircraft 20 is attached to the cam 350 (andthe hub base 100), the fuselage of the fixed-wing aircraft 20 contactsthe front and rear aircraft engaging brackets 340 a and 340 b (toprevent rotation about the pitch and yaw axes of the fixed-wing aircraft20), and the stabilizers 290 a and 290 b contact the wings of thefixed-wing aircraft 20 (to prevent rotation about the roll axis of thefixed-wing aircraft 20).

Since the lock servo motor locking extension 392 a is engaged to the camservo motor arm lock device 382 a of the cam servo motor arm 382, thecam servo motor 381 cannot rotate the cam 350 from the attachedrotational position to the detached rotational position(counter-clockwise from this viewpoint). This prevents undesireddetachment of the fixed-wing aircraft 20 from the cam 350 (and themulticopter 10).

After the hub module 100 is attached to the fixed-wing aircraft 20, theoperator: (1) attaches the front and rear landing gear modules 600 a to600 d to their respective front and rear landing gear extension modules500 a to 500 d; (2) attaches the front and rear landing gear extensionmodules 500 a to 500 d to their respective rotor arm modules 400 a to400 d; and (3) attaches and locks the rotor arm modules 400 a to 400 dto the hub module 100 to complete assembly of the multicopter 10.

The operator ensures the front and rear landing gear modules 600 a to600 d are not in the path of rotation of the rotors of theircorresponding rotor arm modules 400 a to 400 b, and connects the mainpower line of the multicopter 10 to switch a main power circuit to aclosed state (from an open state). Unlike the idle power circuit, themain power circuit (when closed) is capable of delivering currentsufficient to drive the rotor motors and cause the multicopter 10 tofly.

The operator begins the engine start-up procedure for the fixed-wingaircraft 20. The operator selects the ALTHOLD flight mode for themulticopter 10. The operator (or an assistant) disengages the safetymechanism 2150 of the fuselage-retaining assembly 2130, which enablesthe pincers 2132 and 2134 to separate from the fuselage-retainingorientation to the fuselage-release orientation.

The operator advances the throttle to begin vertically climbing and liftthe fixed-wing aircraft 20 from between the pincers 2132 and 2134 (whichare free to separate and release the fuselage of the fixed-wing aircraft20 since the safety mechanism 2150 is disengaged). Once the multicopter10 and attached fixed-wing aircraft 20 have reached a designatedaltitude, the operator controls the multicopter 10 to begin dashingforward. At this point, if the airspeed, GPS reception, and pitch angleof the fixed-wing aircraft 20 is within a suitable range (e.g., 10 to 20degrees), the multicopter 10 can detach the fixed-wing aircraft 20.

Detaching the fixed-wing aircraft 20 from the cam 350 (and themulticopter 10) is a two-step process, as shown in FIGS. 10A to 10C. Todetach the fixed-wing aircraft 20 from the cam 350 (and the multicopter10), the operator first remotely controls the lock servo motor 391 (viathe R/C controller) to rotate the lock servo motor arm 392 into the camrotation-enabling rotational position (counter-clockwise from thisviewpoint). Second, the operator remotely controls the cam servo motor381 (via the R/C controller) to rotate the cam 350 from the attachedrotational position to the detached rotational position(counter-clockwise from this viewpoint). As shown in the progressionfrom FIGS. 10A to 10C, as the cam servo motor 381 rotates the cam 350from the attached rotational position to the detached rotationalposition, the valley 352 and the ascending edge of the ridge 353 forcesthe hook 21 off of the cam 350, thereby detaching the fixed-wingaircraft 20 from the cam 350 (and the multicopter 10).

After detachment, the operator may switch the multicopter 10 tohalf-power mode and recover the multicopter 10 either manually viaALTHOLD and/or LOITER flight modes or semi-autonomously via RTL flightmode.

At the instant the multicopter 10 contacts the landing surface, ashutdown command may be issued, causing all of the rotor motors to shutdown. In this embodiment, to avoid potential damage to the multicopter10 upon recovery, two conditions must be met before the operator canshut down the rotor motors: (1) the measured altitude of the multicopter10 is below a designated altitude; and (2) the throttle of themulticopter 10 is below a designated threshold.

In certain embodiments, the operator may desire to launch the fixed-wingaircraft 20 from a location in which GPS is unavailable (e.g., from theground in a heavily wooded or mountainous region). In one suchembodiment, the operator may use a GPS repeater to acquire a GPS fix forthe fixed-wing aircraft and/or the multicopter during preflight. In thiscase, the GPS repeater might have a GPS receiving antennae on the roofof a building, on a hilltop, or flying in an aircraft, while pre-flightis happening in the GPS-denied location. The GPS-denied location may bea lower floor in the same building as the one that has the GPS antennaeon the roof. In this case, the operator may decide to seal-off thepreflight area (i.e., close the garage door) to avoid multipath GPSjamming. After preflight is completed, the repeater may be switched offand the seal breached to allow the aircraft to exit the preflight areaand begin attempts to acquire GPS directly. Once launched, thefixed-wing aircraft 20 will acquire that GPS satellite constellationonce able to do so (such as when the multicopter 10 and attachedfixed-wing aircraft 20 climb high enough to acquire GPS). This processis shortened, as the GPS receiver enjoys familiarity with the prevailingsatellite constellation.

In other embodiments in which the operator desires to launch thefixed-wing aircraft 20 from a location in which GPS is unavailable,rather than using a GPS repeater to acquire and pre-load a desired GPSsatellite constellation to the fixed-wing aircraft 20, the operatorsimply climbs the multicopter 10 and attached fixed-wing aircraft 20high enough to acquire GPS. At that point, the fixed-wing aircraft 20acquires the desired GPS satellite constellation, and launch proceeds asdescribed above. The operator can abort launch should the fixed-wingaircraft 20 not be able to acquire GPS. This offers a unique advantageover traditional (ground-based) launch systems that cannot operate fromGPS-denied locations, as the fixed-wing aircraft owner would not acceptthe risk that GPS would be acquired (on faith) during the first fewmoments of flight.

4.2 Multicopter-Assisted Fixed-Wing Aircraft Retrieval Method

To retrieve the fixed-wing aircraft 20 from wing-borne flight, theoperator positions the anchor system 3000 at a desired retrievallocation. The operator attaches the free end of the flexible capturemember 5000 (which is the free end of the elastic portion 5100 in thisembodiment) to the cam 350 of the multicopter 10. The other end of theflexible capture member 5000 is attached to the flexible capture memberpayout and retract device 3300. A length of the flexible capture member5000 (particularly, the retractable portion 5300) is fed through thefairlead 3812 and wound around the drum 3312.

As best shown in FIGS. 10D, 10E, 10F, and 10G, the operator fixedlyattaches (e.g., by knotting) a breakaway ring 3250 to the flexiblecapture member 5000 at a particular point (such as 200 feet or any othersuitable distance from upper end of the flexible capture member 5000).The operator attaches the breakaway ring 3250 to the breakaway device3200 as follows: (1) the operator removes the breakaway sleeve 3220 fromthe collar 3214; (2) the operator rotates the finger 3228 outside of theinterior of the breakaway sleeve 3220; (3) the operator slides thebreakaway ring 3250 onto the finger 3228; (4) the operator rotates thefinger 3228 back inside the interior of the breakaway sleeve 3220; and(5) the operator attaches the breakaway sleeve 3220 to the collar 3214to trap the finger 3228 within, thereby retaining the breakaway ring3250 on the finger 3228.

The operator switches on an idle power circuit of the multicopter 10 toperform various preflight checks, as described above. The operatorselects the LOITER or ALTHOLD flight mode and TENSION throttle mode forthe multicopter 10. The operator ensures the GPS antenna 3810 of theanchor system 3300 has acquired sufficient GPS satellites to enable thefixed-wing aircraft 20 to locate the anchor system 3300 with anacceptable level of uncertainty.

As the fixed-wing aircraft approaches the anchor system 3300, theoperator remotely controls the multicopter 10 to climb to a designatedaltitude above the anchor system 300 and maintain a particular tension(such as 20 pounds) in the portion of the flexible capture member 5000extending between the multicopter 10 and the breakaway ring 3250. Thistension is less than the force required to compress the compressionspring 3216 of the breakaway device 3200 (about 100 to 150 pounds inthis example embodiment). The multicopter 10 station keeps relative tothe anchor system 3300 while above the anchor system 3300. Above in thiscontext, unless described otherwise, means vertically spaced apart from.

As shown in FIG. 10H, the fixed-wing aircraft 20 is flown toward,contacts, and captures part of the capture portion 5000 b of theflexible capture member 5000 in a manner similar to that described inU.S. Pat. No. 6,264,140, the entire contents of which are incorporatedherein by reference. Specifically, the fixed-wing aircraft 20 is flowntoward the capture portion 5200 of the flexible capture member 5000 suchthat the leading edge of one of the wings of the fixed-wing aircraft 20contacts the capture portion 5200. After the leading edge of the wingcontacts the capture portion 5200, continued movement of the fixed-wingaircraft 20 relative to the capture portion 5200 causes the captureportion 5200 to slide away from the fuselage of the fixed-wing aircraft20 along the leading edge of the wing toward the end of the wing until atether capture device (not shown) near the end of the wing captures partof the capture portion 5200.

When the fixed-wing aircraft 20 contacts the flexible capture member5000, the operator advances the throttle of the multicopter 10 tomaximum for a predetermined period of time (such as 3 seconds), thenslowly reduces the throttle to arrest motion and allow the fixed-wingaircraft to controllably descend.

FIGS. 10E, 10F, and 10G show the breakaway device 3300 releasing thebreakaway ring 3250 during capture, thereby enabling the anchor system3000 to begin paying out the retractable portion 5300 of the flexiblecapture member 5000 wound around the drum 312 of the flexible capturemember payout and retract device 3300 to absorb the kinetic energy ofand slow the fixed-wing aircraft 20.

FIG. 10E shows the breakaway device 3300 before capture. The fixed-wingaircraft 20 contacting the flexible capture member 5000 tensions theflexible capture member 5000. Since the flexible capture member 5000 isattached to the breakaway sleeve 3220 via the breakaway ring 3250 thistension imposes a lifting force on the breakaway sleeve 3220 and thecollar 3214 to which the breakaway sleeve 3220 is attached. As bestshown in FIG. 10F, if this lifting force is large enough to overcome thebiasing force of the compression spring 3216, this lifting force causesthe collar 3214 to slide upward relative to the shaft 3210 and compressthe compression spring 3216. As best shown in FIGS. 10F and 10G, oncethe compression spring 3216 is compressed a designated amount, thefinger 3228 is free to escape the breakaway sleeve 3220 through thefinger escape slot 3226. At this point, the tension in the flexiblecapture member 5000 causes the finger 3228 to rotate out of thebreakaway sleeve 3220, thereby releasing the breakaway ring 3250.

Once the breakaway device 3200 releases the breakaway ring 3250,continued motion of the fixed-wing aircraft 20 causes the flexiblecapture member payout and retract device 3300 to begin paying out theretractable portion 5300 of the flexible capture member 5000, initiallywound around the drum 3312. As the flexible capture member payout andretract device 3300 pays out the retractable portion 5300 of theflexible capture member 5000, the flexible capture member payout andretract device 3300 dampens this payout—and absorbs the kinetic energyof the fixed-wing aircraft 20—in two ways: (1) the biasing elementwithin the drum 3312 biasing the drum 3312 to its initial rotationalposition and against the rotation that results in payout of the flexiblecapture member (described above); and (2) eddy current braking(described below).

As indicated above, the electrically conductive flanges 3314 and 3316 ofthe flexible capture member payout and retract device 3300 enable eddycurrents to flow as the flanges move in the vicinity of the magnetsattracted to the backing plates attached to the anchor system base 3100to which the flexible capture member payout and retract device 3300 isattached. As the flanges 3314 and 3316 rotate with the drum 3312relative to the anchor system base 3100—such as while the flexiblecapture member payout and retract device 3300 pays out the flexiblecapture member 5000 during retrieval of the fixed-wing aircraft 20—theflanges 3314 and 3316 move past the stationary magnets. This induceseddy currents to flow, and the resulting drag force tends to opposerotation of the drum 3312. The eddy current drag force increases withincreasing speed and therefore the payout speed is limited.

The fixed-wing aircraft 20 eventually stops moving and dangles below themulticopter 10, as best shown in FIG. 10I. At this point, the biasingelement within the drum 3312 biases the drum 3312 to reverse spindirection, which retracts the retractable portion 5300 of the flexiblecapture member back into the anchor system 3300. Specifically, thiscauses the retractable portion 5300 of the flexible capture member towind back onto the drum 3312. In some embodiments, the flexible capturemember payout and retract device is configured to retract only part ofthe flexible capture member—such as the retractable portion—while inother embodiments the flexible capture member payout and retract deviceis configured to retract all or substantially all of the flexiblecapture member. The flexible capture member payout and retract device incertain embodiments includes a motor-driven payout spool (such as aspool used for fishing or parasailing), a capstan winch (such as thoseused for anchoring a yacht), a clothes wringer, or a stuff sack, such asthose used in sport climbing.

Once the tether capture device of the fixed-wing aircraft 20 capturesthe part of the capture portion 5200, the tether capture device holdsthat part of the capture portion 5200 such that the fixed-wing aircraft20 does not slide down the flexible capture member 5000. If, however,the tether capture device does not initially prevent the fixed-wingaircraft from sliding down the flexible capture member 5000 and thefixed-wing aircraft 20 begins sliding, the increasing thickness of thecapture portion 5200 will eventually arrest this sliding. In otherembodiments, rather than (or in addition to) being thicker at its endsthan in its middle, the capture portion 5200 is knotted along its length(such as every few feet) to prevent the fixed-wing aircraft 20 fromsliding down the capture portion 5200 after capture.

After capture, the operator may engage NORMAL throttle mode to improvecontrol of his descent rate as the flexible capture member 5000 slackensand the fixed-wing aircraft 20 is lowered to the landing surface.Thereafter, the operator may engage the half-power mode and control themulticopter 10 to descend until it reaches ground, at which point theoperator shuts down the rotor motors.

In certain embodiments, the operator desires to retrieve the fixed-wingaircraft 20 from a location in which GPS is unavailable. In theseembodiments, the operator attaches the GPS antenna 3810—normallyattached to the anchor system 3000—to the multicopter 10. This enablesthe GPS antenna 3810 to acquire GPS once the multicopter 10 climbs tothe desired altitude for retrieval.

Various changes and modifications to the presently preferred embodimentsdescribed herein will be apparent to those skilled in the art. Thesechanges and modifications can be made without departing from the spiritand scope of the present subject matter and without diminishing itsintended advantages. It is intended that such changes and modificationsbe covered by the appended claims.

The invention is claimed as follows:
 1. A multicopter comprising:multiple arms each including a rotor and a rotor motor drivingly engagedto the rotor; one or more supports to which the arms are attachable; asuspension attached to the one or more supports and extending at leastpartially above the one or more supports; an isolator plate attached tothe suspension and extending above at least part of the suspension; anavionics enclosure attached to the isolator plate; and a batteryattached to the isolator plate, wherein the battery, the isolator plate,and the suspension are configured to reduce vibration caused by therotors from being transferred through the multiple arms and the one ormore supports to the avionics enclosure.
 2. The multicopter of claim 1,wherein the one or more supports include multiple mounting posts, theisolator plate defines multiple mounting openings, and the mountingposts are respectively receivable in the mounting openings.
 3. Themulticopter of claim 2, wherein the suspension includes multiple firstshock-absorbing elements between the one or more supports and theisolator plate.
 4. The multicopter of claim 3, wherein the firstshock-absorbing elements include springs.
 5. The multicopter of claim 3,wherein the suspension includes multiple second shock-absorbing elementsbetween multiple spring retaining elements and the isolator plate. 6.The multicopter of claim 5, wherein the second shock-absorbing elementsinclude springs.
 7. The multicopter of claim 1, wherein: the one or moresupports include multiple mounting posts, the isolator plate definesmultiple mounting openings, and the mounting posts are respectivelyreceivable in the mounting openings, the suspension includes multiplefirst shock-absorbing elements between the one or more supports and theisolator plate, the suspension includes multiple second shock-absorbingelements between multiple spring retaining elements and the isolatorplate, and the suspension includes a constraining element positioned toenable restricted movement of the one or more supports and the isolatorplate relative to one another.
 8. The multicopter of claim 1, whichincludes an inertial measurement unit attached to the isolator plate. 9.A multicopter comprising: a supporting structure; multiple arms eachincluding a rotor and a rotor motor drivingly coupled to the rotor, eacharm attachable to the supporting structure; a suspension attached to thesupporting structure and extending at least partially above thesupporting structure; an isolator plate attached to the suspension andextending above at least part of the suspension; an avionics enclosureattached to the isolator plate; and a battery attached to the isolatorplate, wherein the battery, the isolator plate, and the suspension areconfigured to reduce vibration caused by the rotors from beingtransferred through the multiple arms and supporting structure to theavionics enclosure.
 10. The multicopter of claim 9, wherein thesupporting structure includes multiple mounting posts, the isolatorplate defines multiple mounting openings, and the mounting posts arerespectively receivable in the mounting openings.
 11. The multicopter ofclaim 9, wherein the suspension includes multiple first shock-absorbingelements between the supporting structure and the isolator plate. 12.The multicopter of claim 11, wherein the first shock-absorbing elementsinclude springs.
 13. The multicopter of claim 12, wherein the suspensionincludes multiple second shock-absorbing elements between multiplespring retaining elements and the isolator plate.
 14. The multicopter ofclaim 13, wherein the second shock-absorbing elements include springs.15. The multicopter of claim 9, wherein: the supporting structureincludes multiple mounting posts, the isolator plate defines multiplemounting openings, and the mounting posts are respectively receivable inthe mounting openings, the suspension includes multiple firstshock-absorbing elements between the supporting structure and theisolator plate, the suspension includes multiple second shock-absorbingelements between multiple spring retaining elements and the isolatorplate, and the suspension includes a constraining element positioned toenable restricted movement of the supporting structure and the isolatorplate relative to one another.
 16. The multicopter of claim 9, whichincludes an inertial measurement unit attached to the isolator plate.17. A multicopter comprising: multiple arms each including a rotor and arotor motor drivingly engaged to the rotor; one or more supports towhich the arms are attachable; an isolator plate; and a suspensionattaching the one or more supports and the isolator plate, wherein: theone or more supports include multiple mounting posts, the isolator platedefines multiple mounting openings, and the mounting posts arerespectively receivable in the mounting openings, the suspensionincludes multiple first shock-absorbing elements between the one or moresupports and the isolator plate, the suspension includes multiple secondshock-absorbing elements between multiple spring retaining elements andthe isolator plate, and the suspension includes a constraining elementpositioned to enable restricted movement of the one or more supports andthe isolator plate relative to one another.
 18. A multicoptercomprising: a supporting structure; multiple arms each including a rotorand a rotor motor drivingly coupled to the rotor, each arm attachable tothe supporting structure; an isolator plate; and a suspension couplingthe supporting structure and the isolator plate, wherein: the supportingstructure includes multiple mounting posts, the isolator plate definesmultiple mounting openings, and the mounting posts are respectivelyreceivable in the mounting openings, the suspension includes multiplefirst shock-absorbing elements between the supporting structure and theisolator plate, the suspension includes multiple second shock-absorbingelements between multiple spring retaining elements and the isolatorplate, and the suspension includes a constraining element positioned toenable restricted movement of the supporting structure and the isolatorplate relative to one another.